Trump is supported by 48% of registered voters in Iowa and Biden is supported by 47%. Just 2% say they will vote for another candidate and 2% are still undecided. Trump led Biden among registered voters in prior Monmouth polls – by 50% to 44% in September and by 48% to 45% in August.

Biden pulls ahead, though, when different likely voter models+ are applied. A model based on a relatively high level of turnout puts the race at 50% Biden and 47% Trump, while a model reflecting lower turnout produces an even wider 51% to 46% result. Trump led by 3 points among likely voters in Monmouth’s poll last month.

Biden’s lead is wider in the lower turnout scenario because of the large number of Democratic ballots that have already been cast. Over one-third (37%) of registered voters say they have already returned their ballots. The overwhelming majority of these votes have gone to Biden (71%) rather than Trump (28%). If turnout ends up being low at this point, it would be due mainly to Republican-leaning Election Day voters deciding to stay home.