CARSON CAMPAIGN CHAIR: 'WE CLEARLY DON'T KNOW' HOW TO WIN

Donald Trump knows what it will take to become the Republican nominee for president: momentum, mostly, formed by the support of blue-collar whites who are angry about trade deficits with China and Mexico, declining middle-class incomes and illegal immigration. Ted Cruz also knows what he needs to win: the strong support of southern evangelicals and his home state, Texas, and for Trump supporters, many of whom don't participate in politics all that often, to stay home on election day. He also needs Marco Rubio to drop out. Rubio, likewise, needs Cruz gone pronto, and he needs to win some states on Super Tuesday—Minnesota is a likely suspect—to create some anti-Trump momentum.

Ben Carson, the retired neurosurgeon and one-time favorite of the Tea Party and evangelical voters before they flocked to Cruz in droves, is less clear about his road to the nomination. "Well, we clearly don't know. We don't have a well defined path to victory," Carson campaign chairman Bob Dees told the Washington Examiner on Tuesday.