Hours before voters will cast ballots in a southwestern Pennsylvania district that President Trump overwhelmingly won, a new poll finds the Democratic candidate winning.

Conor Lamb, a 33-year-old Marine veteran and former prosecutor has jumped ahead in a special-election contest in Pennsylvania’s 18th district on Tuesday, according to the new poll released Monday by Monmouth University.

In three different turnout models, Lamb is set to beat Republican state Rep. Rick Saccone in a district that Trump won by a nearly 20-point margin in the 2016 election.

“Lamb holds a 51% to 45% lead over Saccone if turnout yields a Democratic surge similar to voting patterns seen in other special elections over the past year,” the poll says.

Using a model with lower historical midterm turnout, Lamb still has the edge, according to Monmouth—but that lead is significantly smaller (49% - 47%).

The final model Monmouth used, based on higher overall turnout more akin to a presidential election, finds Lamb with a substantial 51% to 44% lead.

The new numbers represent a major swing towards the Democrat since the last poll Monmouth conducted in February, which found Saccone with small leads in every turnout model.

“This district has voted overwhelmingly Republican in recent elections, but a large number of these voters have blue-collar Democratic roots. Lamb seems to have connected with them,” Patrick Murray, director of the independent polling organization said in conjunction with the data’s release.

Despite a barrage of negative advertising against Lamb, attempting to link him to House Minority Leader Nancy Pelosi (D-CA), he has a net favorable approval rating of 53% - 33%, according to the Monmouth poll.

Interviews for this particular poll were done prior to President Trump’s pro-Saccone rally on Saturday in Pennsylvania, intended in part to talk about his imposition of steel tariffs, which was viewed as a positive for some voters in the district.

However, the polling found that the president’s announcement didn’t do much to move voters in either direction (3% of likely voters said they were moving towards Saccone because of the tariffs while 1% said they were moving towards Lamb).

“A bare plurality of likely PA18 voters say that the tariffs will help (43%) the local area’s economy, but a sizable number (36%) feel these tariffs will actually hurt the region,” the poll claims. “Another 8% say the tariffs will have no impact and 13% are not sure what the impact will be.”

In terms of President Trump’s overall approval, voters in the district are evenly divided according to the poll, with 49% approving and 49% disapproving.

The race to replace disgraced former Rep. Tim Murphy (R-PA), has brought millions and millions of dollars to the vanishing district in the form of Republican outside group investments. Viewed as an anemic fundraiser by many GOP officials, Saccone has been getting air and ground support over the last few days. That included the visit from Trump on Saturday, during which he advocated for the death penalty for drug dealers.

The president has also publicly backed Saccone, urging voters to support him on Tuesday despite the fact that in private, he has reportedly derided him.

Lamb has been rallying union support in the final days of his campaign, hoping to drive up enthusiasm with the large bloc of voters in the district.

He has focused a great deal of his rhetoric on protecting Social Security and Medicare and cast aside any comparisons to the national Democratic party at large.

“I told the press that I wouldn’t support Nancy Pelosi for Speaker or any other leadership position, but I think that is just kind of beside the point,” Lamb told The Daily Beast in an interview last month. “Paul Ryan is the leader that we need to be talking about. And he’s the one that people around here at least know. He’s coming after their social security and Medicare, so they want him gone as well.”