A new Suffolk University/USA Today poll of Iowa Democratic caucus goers has former Vice President Joe Biden and Sen. Elizabeth Warren almost tied for first place, with Mayor Pete Buttigieg showing a significant jump to third place and Sen. Bernie Sanders dropping to single digits. The numbers raise questions about the shifting dynamics of the second-tier candidates jockeying for a position beneath the current top two candidates. Meanwhile, third-tier candidate Rep. Tulsi Gabbard, who has struggled to poll at 2 percent, gained traction in the headlines after Hillary Clinton’s comments about her on a political podcast last week.

To discuss all this and more, Jim Braude was joined by two candidates running in the Democratic primary for Massachusetts’ 4th Congressional district: Newton City Councilor Jake Auchincloss, and City Year co-founder Alan Khazei. Greater Boston will be joined by the other candidates in that race in the weeks to come.