Democratic Massachusetts Senator Elizabeth Warren is pictured. Image via Elizabeth Warren/website

A new poll reveals that not only is Vice President Joe Biden trailing former Secretary of State of Hillary Clinton, but he is also running behind Massachusetts Senator Elizabeth Warren in the key presidential state of Iowa.

The Suffolk University poll of Iowa voters, which was released Wednesday, shows Clinton remains the overwhelming favorite among Democrats (63 percent), followed by Warren (12 percent) and Biden (10 percent). Warren, who is well-liked among progressives, has said she is not running for president in 2016.

“I’m not running for president and I plan to serve out my term,” Warren said in a news conference December. But that may change as many progressives continue to raise the possibility of having a more liberal alternative to both Clinton and Biden. Former labor secretary and liberal economist Robert Reich said Warren may run if progressives feel that other candidates are not speaking passionately enough about the need to tackle issues like income inequality.

“I think, though, if we don’t get a candidate or a set of candidates in 2016 who are taking this issue with the seriousness it needs to be taken, I think that there will be a lot of people – Elizabeth Warren, others, maybe even me – who will toss our hats in the ring, because it has to be addressed,” Reich told The Washington Post in February.

The 2016 Republican field, however, remains divided with former Arkansas Governor Mike Huckabee at 11 percent, followed by Senator Rand Paul of Kentucky and former Florida Governor Jeb Bush (10 percent each). Senator Ted Cruz of Texas and Ben Carson both received 9 percent each, while New Jersey Governor Chris Christie came in at 7 percent.

The Suffolk University poll results are based on interviews of 800 likely voters conducted April 3-8. It has a margin of error of ±3.5 percent.