berlin follow donald trump decision decertify iran nuclear deal month shake european capitals ask u.s. president next diplomats sketch scenarios fear could plunge transatlantic relations crisis trade war military conflict north korea collapse cold war-era arm treaty wonder post-war alliance survive come true since trump take office nine months ago governments berlin paris london waver alarm rhetoric shaky sense bad instincts contain grow up cabinet pressure ally iran decision take despite personal appeal france emmanuel macron germany angela merkel britain theresa may change calculus europe accord diplomats politicians analysts long underlie confidence europe muddle three years trump without fear major possibly last disruptions relationship faith trump stake high listen advisers partner tell anxiety especially acute germany whose identity anchor relationship unite state whose reliance washington particularly defense security matter run deep france britain sense desperation berlin sense trump know stake understand historical factor play say wolfgang ischinger former german ambassador washington chairman munich security conference transatlantic relationship trust sense iran decision take us new level breach trust say trump decision decertify iran deal necessarily kill depend congress must decide impose new sanction tehran consensus europe landmark diplomatic achievement seriously undermine merkel allude breakdown trust back may say europe might able rely unite state must take fate hand come contentious g7 meet sicily trump ignore pleas ally stick another multilateral agreement paris climate accord since merkel focus election efforts form coalition say little transatlantic relationship trump macron meanwhile do best charm american president invite paris bastille day celebrations meet unite nations last month despair make change mind macron say new york trump stances climate iran private however european officials say worry trump rejection iran deal could harbinger disruptive salvos washington one senior european diplomat say next conflict would likely trade describe trump attempt renegotiate north american free trade agreement nafta threats abandon litmus test european firm especially german carmakers produce mexico export unite state could hit hard breakdown nafta also fear trump could carry threat introduce steel import tariff would hit european exporters well chinese far lot bark bite trump trade mean stay way say european diplomat prepare real protectionist measure step penalize european firm directly indirectly would create downward spiral anti-americanism north korea another area concern thorsten benner director global public policy institute berlin believe reaction europe military conflict korean peninsula could messy iraq war european public could view washington aggressor conflict could fuel anti-american sentiment make difficult european leaders stand trump embolden voice already call break washington matter unrealistic look practice wake fact may deal trump time may correction leave one german diplomat tell reuters dawn people existential react concern sentiments lead group dozen germany-based foreign policy experts issue manifesto month entitle spite america warn berlin turn back washington trump former ambassador ischinger share view concern relationship could deteriorate one big fear collapse inf treaty nuclear arm reduction pact sign president ronald reagan soviet leader mikhail gorbachev 1987. washington moscow accuse violate treaty gorbachev warn month peril inf unravel ischinger believe divisive 1980s debate deploy nuclear weapons europe could resurface devastate consequences transatlantic tie hell could break loose politically speak say generations germans ischinger say symbol transatlantic alliance u.s. presidents john f. kennedy reagan bill clinton barack obama long tell children part alliance trump president say rather sad know loss symbol replace iran shock nervous europe gird next trump salvo