Republican presidential candidate, former Massachusetts Gov. Mitt Romney and President Barack Obama walks past each other on stage at the end of the last debate at Lynn University, Monday, Oct. 22, 2012, in Boca Raton, Fla. (AP Photo/Pablo Martinez Monsivais)

A new Hawkeye Poll showing Mitt Romney with a slight lead over President Obama probably is all that’s needed to explain why both candidates will be in Iowa Saturday.

The poll, released Oct. 31, found the GOP challenger leading the president 45.2 percent to 44.4 percent among voters who said they plan to vote.

It also showed a slim majority plans to vote to retain Iowa Supreme Court Justice David Wiggins, who was part of the court’s unanimous decision striking down a state ban on same-sex marriages. That poll found 52.9 percent favored retaining Wiggins while 30.4 said they would vote to oust him. Another 16.7 percent were undecided.

Conducted by a University of Iowa class that wrote the questions, tested the survey and made the calls to a random sample of 320 voting age Iowans, the poll shows Romney “making advances and perhaps taking the lead in Iowa,” according to Frederick Boehmke, associate professor of political science and faculty adviser of the Hawkeye Poll.

“It seems like things are moving his way,” Boehmke said, but cautioned “the race continues to be close and within the margin of error” of 5.6 percent.

So it makes sense for Obama to return to Dubuque Saturday for one more rally aimed at swaying the diminishing number of undecided voters and driving up turnout, Boehmke said.

“Absolutely, I think it’s a good idea for them to fight for every last vote,” he said. “It’s going to be a very close election here and in a lot of other states. There’s a number of scenarios where Iowa is going to be a critical state in this election.”

“Iowa remains up for grabs and it’s understandable and worthwhile for both candidates to continue to spend time here in the remaining few days of the campaign,” added Tim Hagle, UI associate professor of political science.

Given the likelihood Iowa will figure into either candidate wining the Electoral College vote, Boehmke said the race for Iowa “will come down to the on-the-ground campaign, the get-out-the-vote effort.”

Both Romney and Obama have spent considerable time in Iowa, “and I think they feel like they understand the voters here and hope those last efforts are going to be able put them over the top,” Boehmke said.

The Obama visit may be critical, Boehmke said, because while the poll shows Romney ahead among likely voters, the president leads 42.7 percent to 41 percent lead among all respondents whether they plan to vote or not. If he can convince a few of them to vote – and vote for him, Obama could carry Iowa.

On the issue of judicial retention, the poll found that one in five Iowans remains undecided on how to vote. However, a Hawkeye Poll 18 months ago found one in two Iowans was undecided.

Hagel found it surprising that just 76 percent of those polled planned to vote on the judicial retention question.

“It may be that many don’t bother to vote in retentions when they aren’t familiar with the judge or justice involved,” he said.

Support for Wiggins is greatest among Democrats with 85 percent saying they will vote “yes” on retention. Among independents, 49 percent plan to vote “yes” and 32 percent of Republicans said they will vote to retain him.\