Trump slams Cruz over birthplace, donations

A new poll shows Hillary Clinton leads Bernie Sanders by just three points among likely voters in Iowa. In New Hampshire, Sanders leads Clinton by four points. On the Republican side, the Iowa poll shows Ted Cruz leading Donald Trump by four points, but Trump has a 16-point lead in New Hampshire. The GOP race remains volatile, but two distinct plotlines are emerging. Trump and Cruz are battling for supremacy in Iowa, and Marco Rubio and Jeb Bush are fighting to be the mainstream alternative. Major Garrett reports.