washington u.s. president barack obama foreign policy legacy rest part foundation unilateral action successor donald trump could reverse stroke pen due take office jan. 20 trump winner tuesday election campaign time dismantle obama nuclear deal iran reimpose sanction obama ease cuba trump also disagree foreign policy decisions include way obama deploy troop abroad combat islamist militant group notable foreign policy achievements obama democrat use executive authorities offer convenient legal path around republican-controlled congress commit block agenda u.s. constitution give president broad executive power enact foreign policy republican democratic presidents seek exercise power issue executive order presidential memoranda call find obama rely executive authority build foreign policy legacy say thomas wright director project international order strategy brook institution vulnerable countervail executive authority trump administration wright say obama hop pass legacy democrat hillary clinton former secretary state lose presidential election trump republican businessman never hold public office serve military often contradict campaign trump make difficult know sure policies would pursue major constraints include budget cap laws reverse without congress pressure emerge replace policies choose abandon trump say october speech would cancel every unconstitutional executive action memorandum order issue president obama first day office without say would determine constitutionality trump spokeswoman respond request comment thursday late plan perhaps nowhere obama face congressional opposition pursuit 2015 deal iran republicans democrats say put restrictions iran nuclear program return much sanction relief trump vow dismantle although statements deal contradictory president may tighten relax economic sanction executive order anything enact executive order rescind executive order say zachary goldman former u.s. treasury official new york university obama draw enough support democrats block republican-led resolution reject iran deal achieve political victory fall short consensus trump add advantage work u.s. senate house representatives control fellow republicans senate republican leader mitch mcconnell say wednesday hop trump would see much undo unilateral action president take would require us break longstanding u.s. policy another issue obama restore diplomatic tie cuba 2015. face opposition congress lift broad economic embargo especially republicans use executive action ease u.s. sanction obama cap cuba efforts last month sweep presidential policy directive also reversible set forth mandate government engagement people-to-people exchange great u.s. business tie trump take contradictory position whether support embargo obama aid say ease restrictions aim secure enough benefit u.s. businesses travelers would difficult impossible republican president reverse open cuba trump could roll back obama efforts create great transparency drone strike obama issue executive order july require annual disclosures strike commander-in-chief trump wield power mobilize u.s. military short notice without first seek approval congress obama deploy u.s. troop iraq syria libya help fight islamic state militant group rely authority congress grant president george w. bush battle al qaeda authority would allow trump ramp u.s. deployments fight islamist militants choose one former u.s. intelligence official speak condition anonymity say president approve covert action need brief relevant leaders congress operation way trump power however limit pledge expand army grow marine corps boost navy 276 350 ship submarine raise number air force tactical aircraft 1,100 1,200. starters would require congress scrap government spend cap budget control act trump support water-boarding interrogation technique simulate drown also would meet opposition congress last year pass legislation bar use waterboarding extreme interrogation techniques widely consider torture obama sign measure law last november trump could easily erase much obama 's foreign policy legacy