A top poll showing Trump narrowly ahead in Iowa is a warning sign for his campaign

• Donald Trump's lead over Kamala Harris has dwindled since Joe Biden left the race.
• The Des Moines Register's Iowa poll found Trump's lead among likely voters is down to just 4 percentage points.
• Trump is still likely to win Iowa, but the poll underlines the struggles he may face elsewhere.

In 2016, Donald Trump's nine-point victory in Iowa was part of what became a sweeping sea change in the state's politics.

But even as he's favored to win again for the third-straight cycle, a new poll hints that Trump's reelection bid may be in trouble in nearby Midwest states.

Iowa shifted from being a swing state to one where Republicans are firmly in the driver's seat. The Iowa legislature is dominated by the GOP, and the state's congressional delegation now consists solely of Republican lawmakers.

When Trump ran for reelection in 2020, he easily won Iowa, dashing Democrats' hopes of a comeback in a state that, in 2008 and 2012, had backed Barack Obama — whose political career was launched in neighboring Illinois.

Barring a massive political shift, Iowa is set to support Trump in November. In June, before President Joe Biden stepped aside as the Democratic nominee, Trump had a huge 18-point lead (50% to 32%) over Biden in a Des Moines Register/Mediacom Iowa poll of likely voters.

But in a newly released poll from the highly respected pollsters, Trump only led Vice President Kamala Harris by four points (47% to 43%) among likely voters, a stunning figure that shows Harris has made up considerable ground compared to Biden.

Iowa Democrats, like others throughout the country, are overwhelmingly enthusiastic about Harris' candidacy, according to the poll.

But in Iowa, Trump is also faltering with female voters, the poll found, a reflection of an enduring gender gap that threatens his chances in the seven swing states he'll need to win in November — and has made the race closer than expected in the Hawkeye State.

If signs of major electoral weaknesses can be found in Iowa, what does that say about his overall chances?

Trump has a female voter problem nationally — and in Iowa

Even in June, when Biden was still in the presidential race, Trump had a low favorable rating among independent women in Iowa.

At the time, women overall favored Biden nationally.

But Harris' entry into the race strengthened her support among female voters across the country. In Iowa, the gender gap is as pronounced as it is in many swing states.

The latest Des Moines Register/Mediacom Iowa poll showed Harris with a 17-point advantage over Trump (53% to 36%) with likely female voters, while male voters supported Trump by a larger 27-point margin (59% to 32%).

On the campaign trail, Trump has touted his three Supreme Court appointments, which led to the 2022 decision that overturned Roe v. Wade and sent the issue of abortion back to the states. It's a decision that continues to haunt Republicans across the country, as the party has suffered myriad electoral losses over the past two years tied to issues involving reproductive rights.

In July, a six-week abortion ban went into effect in Iowa. It's a reflection of the agenda of the state's GOP-led legislature, which championed the law.

But in an Iowa poll conducted last year , 61% of all voters said abortion should be legal "in most or all cases," with 70% of Iowa women expressing that opinion.

In the latest Iowa poll, state voters gave Harris an 11-point point edge over Trump (53% to 42%) on the issue of abortion. On every other major issue polled, from immigration to housing prices, Trump held an advantage over the vice president.

Trump has struggled to refine his messaging on the issue for swing voters in key states like Georgia and Pennsylvania, which has given Harris a major opening.

And it currently works to her advantage. Abortion isn't an issue that can be neatly put in an ideological, partisan box. There are Republican voters who back some form of abortion rights despite the GOP's overall anti-abortion stance.

That's created trouble for Trump among voters of all stripes, even in Iowa.

Meanwhile, Harris has clearly changed the race.

National polling mirrors what the Iowa survey found regarding an explosion of enthusiasm among the Democratic base. This is one of the main reasons that Trump's massive lead is now trending closer to his 2020 margin. The Iowa poll found that Iowans under age 45 are now 10 points more likely to vote, while voters with a college degree are nine points more likely to vote and those who live in cities are now six points more likely to vote.

"This poll may be catching newly energized voters who thought they would sit out the election at the time our June poll was taken," pollster J. Ann Selzer told The Register.

Trump's slim Iowa lead could point to problems in more competitive states

Trump is still heavily favored to prevail in Iowa. Election forecaster Nate Silver's model gives the former president overwhelming odds to carry its six electoral votes. After all, Democrats control just one of the statewide offices.

Still, the poll shows why the intense focus on the seven swing states can sometimes be detrimental. Look no further than former independent presidential candidate Robert F. Kennedy Jr., the longtime Democrat who endorsed Trump and abandoned his third-party run.

Kennedy is fighting to get off the ballot in swing states, but he missed the deadline to remove himself from the Iowa ballot.

The Iowa poll found that six percent of voters still back Kennedy, a decrease from June but still a number that could cause headaches. It's also not certain that Kennedy will get his wish to be taken off the ballot in every swing state, as Wisconsin officials and Michigan's highest court have rejected his efforts .

An equally intriguing poll of Alaska, a state that is notoriously difficult to survey, showed Trump with only a five-percentage point lead there — despite carrying Alaska by just over ten points in 2020. Thanks to at-large Rep. Mary Peltola, there are actually more Democrats in Alaska's congressional delegation than Iowa's, even though a Democratic presidential nominee has only carried Alaska once (Lyndon B. Johnson in 1964) since it was admitted to the union.

It's far more likely that the Iowa survey illustrates Trump's struggles elsewhere.

The poll found that Harris performs best with voters who live in the suburbs and those with a college degree, two demographics where Trump has long had problems.

The good news for Trump is that the Iowa poll shows he's doing well among rural voters and those without a college degree, two groups that fueled his 2016 victory over former Secretary of State Hillary Clinton.

Trump and Iowa Republicans have relied heavily on working-class voters to make the state more red.

And working-class voters hold considerable sway in key states like Michigan, Wisconsin, and Pennsylvania. If Trump hopes to regain the White House, he'll need to make sure his gains among the working class outweigh his losses among women.