new york donald trump take 20-point lead u.s. senator ted cruz texas republican race presidential nomination bolster position ahead party primary south carolina saturday accord national reuters/ipsos poll among republicans trump billionaire businessman draw 40 percent support poll conduct saturday wednesday compare 17 percent cruz 11 percent u.s. senator marco rubio florida 10 percent retire neurosurgeon ben carson percent former florida governor jeb bush result contrast national poll conduct week nbc news wall street journal show trump drop national dead heat cruz race republican nomination nov. election succeed democratic president barack obama democratic side reuters/ipsos poll show former secretary state hillary clinton maintain 10-point national lead u.s. senator bernie sanders vermont since last week new hampshire primary sanders republican result mark nominal gain trump since win feb. new hampshire primary lead cruz 18.4 point national roll survey although increase remain within poll credibility interval since announce candidacy last summer trump leverage celebrity deep pocket wage unfiltered campaign upend republican primary lead reuters/ipsos daily track poll since nearly start campaign top bush late july reuters/ipsos poll also show either clinton sanders would win hypothetical general election contest trump clinton would likely win 44 percent support compare 37 percent trump sanders would likely win 44 percent 35 percent poll include responses 476 register republicans 543 register democrats credibility interval percent edit richard valdmanis peter cooney sap sponsor content independently create reuters editorial staff fund part sap otherwise role coverage trump lead republican field nationally 20 point poll