On paper, a Bucks County-based congressional seat held by the GOP looks like the perfect pickup opportunity for Democrats: The district voted for Hillary Clinton in 2016. Pennsylvania's new congressional map made it slightly less Republican. Democrats made historic gains in the area's municipal elections last year.

But a new poll shows Republican incumbent Brian Fitzpatrick is ahead in the First Congressional District race by a small margin — and has gained ground since the spring.

Fitzpatrick has a 50 percent to 46 percent edge among likely voters over his Democratic challenger, multimillionaire philanthropist Scott Wallace, according to a survey by Monmouth University using a "standard" turnout model.

Fitzpatrick is out front despite the fact that 54 percent of voters in his district don't approve of President Trump's job performance, and a plurality want Democrats to control Congress.

"When you look at the underlying political environment in this district, you would expect the Democrat to be ahead," Patrick Murray, director of the independent Monmouth University Polling Institute, said in a statement. "But Fitzpatrick has been able to overcome this with a solid reputation among his constituents, while many remain uncertain about Wallace."

That could be bad news for Democrats: The Philadelphia suburbs are seen as critical to the party's chances of taking back the House.

Political observers argue that Fitzpatrick has been successful partly because he's built a brand as a moderate. He voted against repealing the Affordable Care Act, and won the endorsements of powerful labor unions.

But last week, the Cook Political Report changed its rating of the race from being in the "lean Republican column" to a "toss-up," saying Fitzpatrick has "yet to truly pitch voters on his moderation and support from Democrats."

When Monmouth used a model predicting a turnout boost in Democratic voting precincts, the race was a dead heat: 49 percent of voters said they would cast a ballot for Fitzpatrick, while 48 percent sided with Wallace.

With a month to go till Election Day, Fitzpatrick and Wallace both have roughly $1.7 million on hand, according to the most recent campaign finance reports. Spending likely won't end there, though: Wallace is a self-funder, and several outside groups are pouring money into the race.

The Monmouth University poll, which surveyed 353 likely voters between Sept. 27 and Oct. 1, found that Fitzpatrick leads with both men and women as well as white voters without a college degree. Wallace is favored over Fitzpatrick among black, Asian, and Latino voters.

White voters with a college degree are split: 50 percent support Fitzpatrick, while 49 percent are for Wallace.

Fitzpatrick was ahead by only one point in a typical turnout model when Monmouth polled voters from May 31 to June 3. At the time, Wallace enjoyed more support than Fitzpatrick among college-educated white voters (54 percent to 42 percent) and women (56 percent to 40 percent).

The survey by Monmouth University has a margin of error for the candidates' vote share of plus or minus 7.4 percentage points.

When Fitzpatrick won the seat in 2016, he captured 54 percent of the vote. He replaced his brother, Mike Fitzpatrick, a four-term incumbent.