Sarah, a lifelong Republican from Mechanicsburg, Pa., looks pained as she says in a video that she will vote for Democrat Joe Biden over President Donald Trump. “He says he puts America first, but it’s clear he only knows how to put Trump first,” she says.

It might have been the work of Democrats. But the ad, set to begin running Monday in Pennsylvania, was produced by Republican Voters Against Trump (RVAT), a group waging guerrilla warfare within the GOP.

The group has bought $1 million in airtime for TV ads, and will start with an ad on Fox News on Sunday across Pennsylvania. On Monday, a week’s worth of ads featuring two Pennsylvanians will begin running on television and digital platforms in the Harrisburg media market. The group says that ad buy is budgeted at several hundred thousand dollars.

“We believe Joe Biden can take Pennsylvania on the back of former Republicans and former Trump voters,” Tim Miller, political director of RVAT. “That’s a swing constituency that can carry the state.”

Trump carried Pennsylvania by about 44,000 votes, or less than a percentage point, in 2016, and the state figures prominently in the electoral strategies of both parties.

Harrisburg’s media market sprawls through the central part of the state and reaches the Philadelphia exurbs. It is becoming more of a swing region, Miller noted. The target audience: “soft” Republicans and 2016 Trump voters.

The effort is one piece of a $10 million to $15 million ad campaign RVAT is launching in battleground states, including Arizona, North Carolina, Michigan, and Wisconsin.

In addition to Sarah, the Pennsylvania ad will also feature James, a Trump voter from Pittsburgh who says he will not support him this year because, he says, the president foments “hate.”

Recent polling has shown that about 80% to 88% of Republicans say they will vote for Trump, potentially leaving a small persuadable group that could be critical in the battleground states.

RVAT is a project of Defending Democracy Together, a 501(c)(4) advocacy organization made up of Republican operatives and officials from former GOP administrations who believe that Trump has violated traditional party principles and democratic norms.