Sen. Ted Cruz (R-Texas) has jumped businessman Donald Trump for the lead in the first-in-the-nation Iowa caucus, according to a new Des Moines Register/Bloomberg poll released Saturday. Cruz paces the field with 31 percent support, followed by Trump at 21 percent, and retired neurosurgeon Ben Carson at 13 percent. The last iteration of the poll, released Oct. 25, showed Carson with 28 percent support in the state, beating Trump's 19 percent, with Cruz at 10 percent. But Carson fell from the top spot just as quickly as he rose, after the primary race shifted toward foreign policy in the wake...