Republican Senator: Sanders poses biggest threat to Trump; Newly-revealed audio: Bloomberg talks "backhanded" Obama endorsement, thought Romney could have done a better job; Soon: Nevada to award final delegates, Bernie Sanders leading; Sources: Trump ins

Trump: Sanders is like me, but I have a "much bigger base"; Sanders rises in polls as trump says he's "like me"; Dems, GOP slam Sanders for saying "it's unfair to simply say everything is bad" about Fidel Castro's regime; Bloomberg campaign calls on Sanders to denounce vandalism of campaign offices, says his rhetoric is to blame; Biden on Bloomberg audio: "He's still a Republican at heart"; Joe Biden hold campaign rally in South Carolina as new poll shows a tight race with Bernie Sanders; New South Carolina poll: Joe Biden holds narrow lead over Bernie Sanders; National Security Adviser says he has seen no intel indicating Russia wants to help Trump;To learn more about how CNN protects listener privacy, visit cnn.com/privacy Learn more about your ad choices. Visit podcastchoices.com/adchoices