The Senate race in Iowa between Republican Sen. Joni Ernst and Democratic challenger Theresa Greenfield remains tight, according to a new poll. 

Greenfield leads Ernst by 3 percentage points, 45 percent to 42 percent among likely voters, according to a Des Moines Register/Mediacom Iowa poll released Sunday. Greenfield’s lead is within the poll’s 3.8 percentage point margin of error. 

The poll also found that 3 percent of likely voters said they would vote for someone else. Two percent said they would not vote and 7 percent said they are unsure. 

Less than two months until Election Day, the make up of the race remains largely unchanged since a similar poll in June when she led Ernst 46 percent to 43 percent, according to the Des Moines Register. 

Among likely voters, the poll found 75 percent said their minds are made up, up from 68 percent who said the same in June. Another 14 percent said they would still be persuaded, according to the Des Moines Register. 

The poll found Ernst supporters were less likely to say they can be persuaded, with 87 percent saying their minds are made up, compared to the 83 percent of Greenfield supporters who said the same, the Register reported. 

Ernst is one of the most vulnerable Republicans facing reelection. She is one of six Senate Republicans in a race ranked as a “toss up” by The Cook Political Report. 

If Greenfield wins her election, it could help Democrats in their goal of flipping the Senate majority. To do so, Democrats need to pick up three or four seats, depending on which party wins control of the White House. 

GOP Senators in Arizona, North Carolina, Montana, Maine, Georgia and Colorado are also facing tough reelection campaigns. 

The Iowa poll was conducted Sept. 14-17 and includes response from 803 Iowa adults, including 658 likely voters. Questions asked of Iowa adults have a margin of error of 3.5 percentage points. Questions asked of likely voters have a margin of error of plus or minus 3.8 percentage points.