In the early voting states, Senator Elizabeth Warren leads in New Hampshire, while Senator Bernie Sanders leads in Nevada. Meanwhile, former vice president Joe Biden now clings to a narrow lead over Warren in a CBS News/YouGov Tracker estimate of convention delegates -- the only count that ultimately matters -- with an estimated 600 delegates of all delegates available through Super Tuesday, to Warren's 545. CBSN political reporter Caitlin Huey-Burns sits down with Warren to discuss why she is gaining in the polls.
