durham n.h. democrat hillary clinton go attack rival bernie sanders thursday contentious presidential debate yet question whether ambitious proposals viable accuse artful smear suggest could buy political donations sanders fight back repeatedly question clinton progressive credentials portray creature political establishment debate feature heat exchange healthcare college tuition fund efforts rein wall street intensity reflect race see clinton prohibitive lead poll shrivel sanders two vie democratic nomination nov. election one clinton forceful remark come response suggestion sanders could influence political donations wall street enough enough get something say say directly say find ever change view vote donation ever receive think time end artful smear campaign carry say clinton charge sanders proposal single-payer universal healthcare coverage would jeopardize obamacare call great mistake say plan free college education would costly realistic get things do make promise keep clinton say sanders say would dismantle obamacare would expand point many countries provide universal healthcare accept belief unite state america sanders say move forward rally american people believe healthcare all sanders say proposal free tuition public universities would pay tax wall street speculation middle class bail wall street time need wall street time help middle class say five days new hampshire hold second state-by-state presidential nominate contest opinion poll show sanders u.s. senator neighbor vermont double-digit lead clinton surprise front-runner finish barely behind iowa monday clinton seem energize underdog status new hampshire deliver aggressive debate performance campaign reminiscent 2008 run barack obama also begin front-runner become sharp less cautious candidate begin lose debate first since former maryland governor martin malley drop monday poor finish iowa give two candidates freedom directly engage sanders accuse clinton represent establishment say represent ordinary work americans also note super pac take contributions wall street firm clinton receive big speak fee goldman sachs clinton dispute establishment label say quite amuse accuse woman run first woman president establishment two battle best represent progressive ideals sanders say would lead political revolution clinton question ability get proposals republican-led congress progressive someone make progress say attack sanders credentials progressive bring vote 1993 brady bill mandate federal background check gun purchase 2005 vote bill protect gun manufacturers dealers lawsuits go get label think particularly progressive vote brady bill five time say think progressive vote give gun makers sellers immunity sanders repeat early pledge attack clinton controversy use private email account private server government business secretary state politicize say sanders renew attack clinton senate vote authorize u.s. invasion iraq since call mistake point vote war say lead rise islamic state militant group look differ clinton respond vote 2002 plan defeat isis look threats face right now clinton try play expectations performance new hampshire come behind upset victory 2008 campaign days lose badly obama iowa surprisingly strong performance sanders iowa likely prolong race clinton enter presumptive front-runner addition previously schedule debate wisconsin florida candidates add one march flint michigan draw attention city contaminate water crisis ahead michigan primary also debate april may additional report alana wise megan cassella write john whitesides edit leslie adler jonathan oatis sap sponsor content independently create reuters editorial staff fund part sap otherwise role coverage contentious debate clinton sanders claim 'progressive mantle