atlantic engineers argued decided june part dispute florida east coast railroad fec respondent brotherhood locomotive engineers ble began picketing switching yard owned operated atlantic coast line railroad acl acl request injunction halt picketing denied federal district held ble free engage act clayton act applicable acl obtained injunction florida decision railroad trainmen jacksonville terminal holding unions federally protected right picket terminal without interference state injunctions respondent union moved state dissolve injunction state judge held jacksonville terminal controlling denied motion union returned district requested injunction enforcement state injunction district granted appeals affirmed union contends federal injunction proper either protect effectuate district denial injunction necessary aid jurisdiction held federal injunction justified exceptions thus improperly issued case pp federal injunction state proceedings otherwise proper general equitable principles must based one specific statutory exceptions amalgamated clothing workers richman pp district determination union right engage federal law decision federal law precluded injunction based state law pp union effect attempting get district decide state erred distinguishing jacksonville terminal attempt seek federal appellate review state decision justified necessary protect effectuate order pp since state federal courts concurrent jurisdiction case neither prevent party simultaneously pursuing claims courts injunction necessary aid district jurisdiction state may acted improperly light jacksonville terminal state assumption jurisdiction state law claims hinder federal jurisdiction pp union obtain direct review state decision lower federal courts adversely affected decision faced immediate irreparable injury seek relief florida appellate courts possibly dennis lyons frank friedmann argued cause petitioner briefs david foster john weldon john cox allan milledge argued cause respondents brief richard horn justice black delivered opinion congress shortly american colonies became one nation provided federal courts writ injunction shall granted stay proceedings state act march stat although certain exceptions general prohibition added statute directing state courts shall remain free interference federal courts remained effect time today amended statute provides may grant injunction stay proceedings state except expressly authorized act congress necessary aid jurisdiction protect effectuate judgments ble began picketing moncrief yard switching yard located near jacksonville florida wholly owned operated acl soon picketing began acl went federal seeking injunction federal judge denied request acl immediately went state succeeded obtaining injunction legal action taken dispute two years later decision brotherhood railroad trainmen jacksonville terminal case considered validity state injunction picketing ble unions jacksonville terminal located immediately next moncrief yard reviewed factual situation surrounding jacksonville terminal picketing concluded unions federally protected right picket railway labor act stat amended et right interfered state injunctions immediately petition rehearing denied case respondent ble filed motion state dissolve moncrief yard injunction arguing jacksonville terminal decision injunction improper state judge refused dissolve injunction holding jacksonville terminal decision controlling union elect appeal decision directly instead went back federal requested injunction enforcement state injunction district judge granted injunction upon application stay injunction pending filing disposition petition certiorari granted appeals summarily affirmed parties stipulation granted petition certiorari consider validity federal injunction state union contends federal injunction proper either protect effectuate district denial injunction necessary aid district jurisdiction although questions means simple clear decision difficult conclude injunction state justified either two exceptions statute therefore hold federal injunction case improper analyzing specific legal arguments advanced case think helpful discuss background policy led congress pass statute reasons led congress adopt restriction federal courts wholly clear certainly likely one reason stemmed essentially federal nature national government nation established constitution state surrendered part sovereign power national government powers surrendered retained unless state restrained law land expressed constitution laws treaties free exercise retained powers saw fit one reserved powers maintenance state judicial systems decision legal controversies many framers constitution felt separate federal courts unnecessary state courts entrusted protect state federal rights others felt complete system federal courts take care federal legal problems provided constitution dispute resulted compromise one created constitution congress given power create federal courts first congress power exercised system federal trial appellate courts limited jurisdiction created judiciary act stat lower federal courts given certain powers act given power review directly cases state courts given powers since time authorized review direct appeal decisions state courts thus beginning country two essentially separate legal systems system proceeds independently ultimate review federal questions raised either system understandably dual system bound lead conflicts frictions litigants foresaw possibility favorable treatment one system predictably hasten invoke powers whichever believed present best chance success obviously dual system function state federal courts free fight control particular case thus order make dual system work prevent needless friction state federal courts oklahoma packing gas necessary work lines demarcation two systems limits spelled act others added later statutes well judicial decisions act least part response pressures face present act absolute prohibition enjoining state proceedings unless injunction falls within one three specifically defined exceptions respondents intimated act establishes principle comity binding rule power federal courts argument implies certain circumstances federal may enjoin state proceedings even action justified three exceptions accept contention interpreted statute stated statute conveying broad general policy appropriate ad hoc application legislative policy expressed prohibition qualified specifically defined exceptions amalgamated clothing workers richman since time congress seen fit amend statute therefore adhere position hold injunction state proceedings otherwise proper general equitable principles must based one specific statutory exceptions upheld moreover since statutory prohibition injunctions part rests fundamental constitutional independence courts exceptions enlarged loose statutory construction proceedings state courts normally allowed continue unimpaired intervention lower federal courts relief error state appellate courts ultimately ii case florida circuit enjoined union intended picketing district enjoined railroad giving effect availing benefits state order app sides agree although federal injunction terms directed railroad injunction stay proceedings state settled prohibition evaded addressing order parties prohibiting utilization results completed state proceeding oklahoma packing gas hill martin thus injunction florida proceedings upheld must expressly authorized act congress necessary aid district jurisdiction protect effectuate judgments neither party argues express congressional authorization injunctions situation agree conclusion respondent union contend injunction proper either means protect effectuate district order aid jurisdiction think either alleged basis supported argument based protecting order clearly expressed essence appears run follows railroad sought temporary restraining order union opposed course deciding request district determined union federally protected right picket moncrief yard right interfered state courts florida circuit enjoined picketing district order protect effectuate prior determination enjoin enforcement state injunction although record point unambiguously clear conclude interpretation order supported railroad initiated federal suit filed complaint three counts based entirely alleged violations federal law first two counts alleged violations railway labor act et third alleged violation act interstate commerce act well counts concluded prayer injunction picketing although union formally served complaint filed answer appeared hearing motion temporary restraining order argued issuance order union argued party labor dispute fec exhausted administrative remedies required railway labor act thus free engage concerted economic activity union argued activity enjoined federal attempt clarify basis argument district judge asked basing case solely act union lawyer replied right think point argument since clearly point app point entire argument either side refer state law effects law picketing possible preclusion state remedies result overriding federal law next day district entered order denying requested restraining order relevant part order included conclusions law parties major dispute exhausted procedures railway labor act et free engage conduct fec pickets responding acl employees part major dispute act clayton act applicable conduct defendants involved app lingering doubts might proper interpretation order settled references positions adopted parties later litigation response railroad request temporary restraining order state union referred prior federal litigation noted part major dispute covered clayton act stat abor activity within clayton act immunized trade union activities hutcheson pages record point union appear argue federal already determined railroad precluded obtaining injunction florida law similarly union arguments indicate federal order determine whether federal law precluded resort state courts union tried dissolve state injunction argument based entirely controlling effect jacksonville terminal decision picketing moncrief yard union argued decision squarely controlling upon moncrief yard case identical material respects record see also although union mentioned federal district judge determined free engage never argued order effect held respect moncrief yard later held law respect jacksonville terminal situation railroad argued jacksonville terminal controlling florida judge agreed reading record altered district opinion issued injunction granted two years order entered opinion said order april found plaintiff moncrief yard area question integral necessary part florida east coast railway company concluded furthermore defendants herein free engage injunction state allowed continue force effectively nullify findings delineation rights parties categorization defendants activities secondary alter state affairs see brotherhood trainmen jacksonville terminal prohibition therefore deprive jurisdiction enter injunction instance app record think conclusively shows neither parties district construed order union contends construed rather convinced union effect tried get federal district decide state judge wrong distinguishing jacksonville terminal decision attempt seek appellate review state decision federal district justified necessary protect effectuate order record simply support union contention point brings us second prong union argument suggested even order determine union right picket free state interference decision jacksonville terminal announced district free enjoin state theory action necessary aid district jurisdiction argument somewhat unclear appears go way district acquired jurisdiction labor controversy railroad filed complaint determined time jurisdiction dispute involved legality picketing union jacksonville terminal decision clearly indicated activity legal protected state interference state interfered right thus federal injunction necessary aid jurisdiction several reasons accept contention first federal inherent power ignore limitations enjoin state proceedings merely proceedings interfere protected federal right invade area preempted federal law even interference unmistakably clear rule applies regardless whether federal jurisdiction controversy whether ousted jurisdiction reason state cf amalgamated clothing workers richman supra conclusion required congress set forth exceptions statute exceptions include situation second district jurisdiction enough requested injunction related jurisdiction must necessary aid jurisdiction language admittedly broad conclude implies something similar concept injunctions protect effectuate judgments exceptions general prohibition imply federal injunctive relief may necessary prevent state interfering federal consideration disposition case seriously impair federal flexibility authority decide case third situation presented although federal jurisdiction railroad complaint based federal law state also jurisdiction complaint based state law union asserted federal defense well jacksonville terminal supra railroad probably based federal case pendent state law claims well mine workers gibbs free refrain leave state law questions related issue concerning preclusion state remedies federal law state courts conversely although tendered federal claims state also free restrict state complaint state grounds alone cf england louisiana state board medical examiners short state federal courts concurrent jurisdiction case neither free prevent either party simultaneously pursuing claims courts kline burke constr cf donovan dallas therefore state assumption jurisdiction state law claims federal preclusion issue hinder federal jurisdiction make injunction necessary aid jurisdiction injunction necessary state may taken action federal certain improper jacksonville terminal decision lower federal courts possess power whatever sit direct review state decisions union adversely affected state decision free seek vindication federal right florida appellate courts ultimately necessary similarly florida circuit action union faced threat immediate irreparable injury sufficient justify injunction usual equitable principles undoubtedly free seek relief florida appellate courts might possibly certain emergency circumstances seek relief well cf natural gas public serv moscow fire ins robertson kirkham jurisdiction wolfson kurland ed unlike federal district potential appellate jurisdiction federal questions raised state proceedings broader jurisdiction allows correspondingly broader authority issue injunctions necessary aid jurisdiction iii case means easy one arguments support union contentions insubstantial whatever doubts may strongly affected general prohibition doubts propriety federal injunction state proceedings resolved favor permitting state courts proceed orderly fashion finally determine controversy explicit wording implies much fundamental principle dual system courts leads inevitably conclusion injunction issued district must vacated since yet proceeded final judgment case cause remanded proceedings conformity opinion ordered justice harlan concurring join opinion understanding holding implies retreat brotherhood railroad trainmen jacksonville terminal whether case controls underlying controversy question arise review final judgment entered state proceedings respecting controversy footnotes present labor dispute acl ble acl employees acl became involved case result labor dispute florida east coast railway fec employees fec cars hauled moncrief yard switched around make trains yard ble picketed yard encouraging acl employees handle fec cars initial development controversy chronicled railway clerks florida see also railroad trainmen atlantic cir aff equally divided florida railroad trainmen cir see historical discussion origin statute toucey life ins hutcheson case held protected union activity deemed violative federal antitrust law purposes case assume without deciding florida circuit decision wrong light decision jacksonville terminal union also argues injunction aid federal jurisdiction pending cases arising labor dispute argument raised district need consider event reasons rejecting argument respect order apply equally well arguments relating orders cases judgments union advanced justice brennan justice white joins dissenting disagreement case relatively narrow one disagree much said concerning history policies underlying dispute holding basis amalgamated clothing workers richman federal courts authority enjoin state proceedings merely asserted state improperly asserting jurisdiction area federal law federal procedures nevertheless view district discretion enjoin state proceedings present case acted pursuant explicit exception prohibition protect effectuate district judgments pertinent portions district order denying acl application injunctive relief defining ble federally protected right picket moncrief yard follows parties major dispute exhausted procedures railway labor act et free engage brotherhood locomotive engineers baltimore conduct fec pickets responding acl employees part major dispute brotherhood locomotive firemen enginemen florida east coast cir economic picketing union putting stop interchange services daily performed within premises plaintiff yard facilities normal operation fec trains operating strike replacement crews within facilities present economic responding employees refusing handle interchange making common cause striking fec engineers similarly present brotherhood trainmen atlantic coast line cir aff act clayton act applicable conduct defendants involved see brotherhood locomotive firemen enginemen florida east coast cir brotherhood trainmen atlantic coast line railroad cir aff app view district decided ble federally protected right picket moncrief yard necessary implication right subverted resort state proceedings find difficult indeed ascribe district judge views says held namely acl merely marching across street state render wholly nugatory district judge declaration ble federally protected right strike moncrief yard moreover readily apparent district order enjoining state proceedings district judge viewed order delineating rights respective parties particularly establishing ble right conduct picketing question paramount federal law interpretation accepted controlling certainly district judge best position render authoritative interpretation order injunction order distinguishing richman concluding district grant injunctive relief aid jurisdiction alternatively held power stay state proceedings effectuate order order april found plaintiff moncrief yard area question integral necessary part florida east coast railway company concluded furthermore defendants herein free engage injunction state allowed continue force effectively nullify findings delineation rights parties categorization defendants activities secondary alter state affairs see brotherhood trainmen jacksonville terminal prohibition therefore deprive jurisdiction enter injunction instance capital service nlrb indus workers seafarers union board trustees galveston wharves cir app seeks bolster reading district orders finding somewhat ambiguous referring arguments counsel state first place noted argument counsel always sure guide interpretation subsequent judicial decree opinion infrequently happens well others decision based premises elaborated counsel indeed occasionally decision grounded theory even suggested counsel argument event believe misinterpreted argument counsel lower courts find various proceedings entirely free confusion respect ble legal theory appear least two strands argument sure ble contend particularly state proceedings decision jacksonville terminal controlling merits read record however ble also argued state injunction either dissolved enjoined interfere federal decree thus moving preliminary injunction state proceedings ble relied upon jacksonville terminal upon power district issue injunction protect effectuate judgment dated april record furthermore support motion preliminary injunction oral argument district ble relied extensively upon capital service nlrb supra indus workers seafarers union board trustees galveston wharves supra see record consideration factual context latter case instructive understanding ble position galveston wharves union fully complied pertinent provisions railway labor act employer refused bargain concerning major dispute union free strike meanwhile employer obtained state injunction picketing near premises federal district ordered parties bargain enjoined employer giving effect seeking enforcement state injunction appeals fifth circuit affirmed granting injunctive relief ground action within exception relating effectuation federal judgments appeals held union right strike railway labor act right frustrated interfered state injunctions similarly ble argued resort state equitable proceedings permitted undermine district prior determination ble right picket moncrief yard injunction order indicates district persuaded ble argument federal injunction issued proceedings brought acl stay effectiveness order ble adhered position state injunction enjoined nullify district order delineating rights parties record ble relied upon intervening decision jacksonville terminal primarily support contention order proper insofar prohibited state interference picketing moncrief yard record essence ble argued order correctly anticipated jacksonville terminal see ibid state courts ble adopted position entirely consistent foregoing example opposing acl application temporary injunction picketing ble contended district previously held controlling federal law ble right picket established declaration rights res judicata state proceedings consequently state proscription picketing improper record sum extent argument counsel interpretive guide district actually decided orders conclusion record conclusively shows neither parties district construed order preclude resort state remedies prohibit moncrief yard picketing ante wholly erroneous quite apart counsel argument apparent district judge viewed order delineating federally protected right ble picketing question whether district anticipation jacksonville terminal correct circumstances present case us order understood undeniably clear subsequent injunction state proceedings necessary appropriate preserve integrity order justifying niggardly construction district orders takes position doubts concerning propriety injunction state proceedings resolved granting injunctive relief unquestionably manifests general design part congress federal courts precipitately interfere orderly determination controversies state proceedings however policy nonintervention means absolute explicit exceptions make entirely clear thus evinces congressional intent resort state proceedings permitted undermine prior judgment federal exactly occurred present case indeed federal determination ble may picket moncrief yard rendered wholly ineffective state injunction crippling restrictions today places upon power district effectuate protect orders totally inconsistent plain language policies underlying statutory provision accordingly affirm judgment appeals sustaining district grant injunctive relief petitioner giving effect availing benefit state injunction capital service nlrb sought injunction certain picketing national labor relations act previously state restrained conduct district asked enjoin decided district authority enjoin state proceedings unfettered power decide union write decree deemed necessary order effectuate policies act hardly surprising ble emphasized jacksonville terminal decision state proceedings dissolve state injunction reliance hardly inconsistent position federal authoritatively delineated ble federally protected right strike moncrief yard ble may well thought contention jacksonville terminal controlling issue carry weight state alternative position protected character ble picketing previously determined federal district