A new survey out of Iowa is taking a snapshot of the state of the race there ahead of the first GOP debate, finding that President Trump enjoys a distinct advantage in the early-voting state but that voters are considering other candidates as well.

The poll, conducted by Iowa pollster J. Ann Selzer and Selzer and Company for NBC News and the Des Moines Register, found that Mr. Trump leads the field as the first choice for 42 percent of likely Republican caucusgoers.

Governor DeSantis comes in second as the first choice of 19 percent of likely caucusgoers. In third place was Senator Scott, who was the first choice of 9 percent of likely caucusgoers. The former governor of South Carolina and ambassador to the United Nations, Nikki Haley, and Vice President Pence received 6 percent support each.

When considering the second-choice support for candidates, the race appears to become more competitive but still leans Trump, with the former president listed as the first or second choice of 52 percent of caucusgoers.

The combined first and second-place support for Mr. DeSantis was 39 percent. Mr. Scott’s combined first and second-place support was 24 percent. 

For voters whose first choice of candidate is either Mr. Trump or Mr. DeSantis, the poll also asked whether a voter’s “mind is made up” or if the voter “could be persuaded.” Among first-choice supporters of Mr. Trump, 66 percent said that they had made up their minds, while 34 percent said that they could be persuaded.

Among first-choice supporters of Mr. DeSantis, 31 percent said that they had made up their minds, with 69 percent said that they could be persuaded.

For comparison, among all likely Republican caucusgoers, 40 percent said that they had made up their minds about who they are supporting, and 52 percent said that they could be persuaded.

The poll also found that, despite much concern over the electability of Mr. Trump, given his baggage as a candidate, respondents were more likely to support the candidate whose views align more closely with their own rather than the most electable candidate.

Among respondents, 65 percent said they would support a candidate “who comes closest to your views on issues,” while 29 percent said they would support a “candidate with the best chance to defeat Joe Biden” if they were forced to choose.

Although Mr. Trump commands a significant lead both as a first-choice candidate and when first and second choices are combined, Ms. Selzer told the Des Moines Register that the race may be “closer than it seems.”

To back up this claim, she pointed to a score called the combined footprint of a candidate, which measures a candidate’s first-choice support, second-choice support, and the potential support from likely caucusgoers who are “actively considering them.”

Going by candidates’ total footprint, the race tightens up, with Mr. Trump having a footprint of 64 percent, Mr. DeSantis at 61 percent, and Mr. Scott at 53 percent.

Ms. Haley places fourth in terms of total footprint at 40 percent, followed by businessman Vivek Ramaswamy with 34 percent support and Mr. Pence with 32 percent support.

The poll of 406 registered voters in Iowa was conducted between August 13 and 17 and has a margin of error of plus or minus 4.9 points.