national harbor md plan block republican presidential candidate donald trump struggle gain traction friday rival candidates reject democrats revel chaos hop would boost chance keep white house country top elect republican house representatives speaker paul ryan say interest effort draft white house race u.s. senator ted cruz conservative presidential hopeful rule deal pick compromise republican candidate party july convention senior party figure see best chance stop unpredictable billionaire d.c. power broke drop someone exactly like establishment happen manifold revolt country cruz say conservative political action conference outside washington want beat donald trump beat donald trump voters say party leaders worry trump would able beat democratic front-runner hillary clinton election time run state vote week super tuesday senior republicans also fear trump plan build wall u.s.-mexican border ban muslims enter unite state turn voters november upset u.s. ally others note past support liberal policies question whether agenda advance think actually carry conservative mantle little crass say michele minter san diego executive assistant attend cpac trump former reality tv star often play set rule cancel plan speak cpac normally essential stop ambitious republicans instead attend rally kansas real estate magnate draw support many blue-collar republicans concern illegal immigration stagnant wag republican nominate contest lead many poll primary contest still come normal republican say huge cheer rally warren michigan retire neurosurgeon ben carson candidate ever challenge trump months-long lead opinion poll officially end white house bid lot people love vote carson say speech cpac hold national harbor maryland new group call committee draft speaker ryan file paper federal election commission thursday seek raise money push ryan republican alternative ryan budget wonk republican vice presidential candidate 2012 see many party unifier take speaker job last year unite establishment republican lawmakers conservative upstarts house flat interest ryan spokeswoman ashlee strong say email friday trump cement front-runner status senior party figure hope deny enough delegate clinch nomination would give chance choose compromise candidate convention cleveland last time happen republican convention 1948 thomas dewey nominate republican national committee chairman reince priebus say 85 90 percent chance party face scenario year mitt romney john mccain party last two presidential nominees call republicans halt trump rise back whichever candidate strong state form tactical vote elect officials rally behind dump trump banner party 31 state governors example line behind alternative five endorse florida senator marco rubio one back cruz sharp contrast previous years governors overwhelmingly endorse party eventual nominee rubio one state far gear could make-or-break contest home state march 15. cruz say saturday plan open 10 campaign offices could effort force rival senator race trump expect extend lead saturday total 155 delegate stake kansas louisiana maine kentucky democrats happy let republicans fight amongst sit back let light dumpster fire wait finish say eddie vale spokesman american bridge clinton-allied group collect negative research republican candidates give us much great video footage could run ads november nothing republicans attack trump vale tell reuters nationally trump support 41 percent republican voters compare 19 percent back cruz 16 percent back rubio accord reuters/ipsos poll data additional report doina chiacu emily stephenson eric beech ginger gibson write andy sullivan edit bill trott alistair bell article fund part sap independently create reuters editorial staff sap editorial involvement creation production republican 'dump trump effort struggle gain traction