A lot can change in four months, and new polling in Iowa suggests seismic shifts among the ever-changing top tier of Democratic presidential candidates. Per a new Suffolk University/USA Today survey of 500 likely Democratic caucus attendees, it's now a three-way race between Joe Biden, Elizabeth Warren, and, in a surprise boost, Pete Buttigieg, with the notable lead Biden once enjoyed dissipating. In the June version of the same poll, Biden took first place with 24% of the poll respondents, with Kamala Harris at 16%, Warren at 13%, and Buttigieg not even on the double-digit map, with just 6%. Last week's poll shows a significantly narrowed gap, with Biden at 18%, Warren at 17%, and Buttigieg at 13%. Harris fell 13 percentage points and is now tied for sixth place.
Meanwhile, Bernie Sanders held steady at 9%. "Iowa is unquestionably up for grabs," Suffolk University Political Research Center head David Paleologos tells USA Today, noting Buttigieg "has found a lane and is accelerating toward the front of the pack, surpassing Bernie Sanders." Both Buttigieg and Warren are siphoning off support from Sanders, per Newsweek: In an Emerson Polling survey of voters last week—which places Warren and Biden in a tie at 23%, with Buttigieg at 16%—Warren took 26% of the vote from caucusgoers who picked Sanders over Hillary Clinton in 2016, with Buttigieg drawing 16%. The current standings aren't set in stone, however: Per the current Suffolk University/USA Today poll, those who say they're undecided has risen to 29%, an 8-point jump. Meanwhile, 63% of those who say they already have a candidate in mind note they could still switch teams. (Read more Election 2020 stories.)