us, and we'll have a fight. >> who will have the advantage in turnout? plus, rough waters. an escalation in the middle east to now a key senator is the to press joe biden on the u.s. role there. is biden's stance widening the rift on the left? the united states is deeply complicit. >> bernie sanders joins me exclusively. ♪ ♪ hello. i'm jake tapper in washington where the state of our union is frozen. tomorrow is one of the single most consequential days in this year's calendar, the iowa caucuses, where donald trump is hoping voters will help him sew up the primary contest before it begins. "the des moines register" poll suggested that mr. trump is well on his way to achieving that goal. nearly half said they would back trump, with trump leading every