Trump flipped Iowa, which had previously voted twice for President Barack Obama, defeating Democratic nominee Hillary Clinton there by a 51-42 margin in 2016, leading some to believe the state was out of Biden’s reach this fall until polls showed a closer race.

But while the poll indicates a growing lead for the president in Iowa, it shows the Senate race between Republican Sen. Joni Ernst and Democrat Theresa Greenfield getting tighter.

Ernst and Greenfield are now tied, with both women receiving 47 percent support among registered voters, compared to a month ago when Ernst held a 3-point lead.

Ernst falls behind, though, when the poll's data is weighted to consider two different likely voter models — one with a higher projected turnout than in 2016 and one with a lower projected turnout.

Under a high-turnout scenario, Greenfield receives 49 percent to Ernst’s 46 percent, while under the lower turnout scenario Greenfield receives 48 percent to Ernst’s 47 percent.

The poll, which was conducted following the death of Supreme Court Justice Ruth Bader Ginsburg last week, found a divided electorate when it comes to the president’s pledge to fill her vacant seat prior to the election. Half of those polled said they would not approve of Trump trying to install Ginsburg’s replacement before Election Day, with 47 percent saying they would approve of such a move.

That number rises slightly to 48 percent when voters were asked whether they would approve of Trump confirming a new justice after the election if Biden were to win, compared to 49 percent who would not approve.

The Monmouth poll was conducted by phone from Sept. 18-22, with 402 registered voters in Iowa. Results from the survey have a margin of error of plus or minus 4.9 percentage points.