Republican strategists are nervous that a special election for a Congressional seat from Pennsylvania could be a repeat of the GOP’s embarrassing upset loss of an Alabama Senate seat in December. Though the district voted for Trump by 19 points, recent polls have placed Democratic challenger Conor Lamb within striking distance of the Republican, Rick Saccone, a state legislator. Now, national Republican leaders are pouring energy and resources in the campaign, in an effort to stall  the momentum Democrats have enjoyed in races from Virginia to New Jersey, Wisconsin, Washington, and, yes, Alabama.

Describing it as a “bellwether,” Theodore Kupfer writes in the conservative National Review that the race to represent this district, in the western corner of the state bordering Ohio and West Virginia, “is as likely as any to answer the question on everyone’s mind ahead of November: Does the Republican message still resonate in Trump Country?”

Democrats hope they have recruited the ideal challenger. Lamb, 33, is a former federal prosecutor and served in the Marines. He’s from a political family with deep ties in the region. Up until now, he has energetically outraised Saccone, 59–though an infusion of contributions from Republicans lawmakers and PACs has helped Saccone secure more TV air time in recent days. The ads try hard to tie Lamb to Washington liberals like House Minority Leader Nancy Pelosi.

To further bolster Saccone’s campaign, Vice President Mike Pence attended a rally and fundraiser with the candidate last week, and other top officials–perhaps even President Trump himself–are likely to stump for Saccone between now and the March 13 election.

Voters in the district “know me, they know my family,” Lamb told  Politico. “They don’t care what Mike Pence says.”

The March election sets up the first of three contests between now and November for the seat, which was prompted by the resignation of Republican Rep. Tim Murphy. Murphy quit after reports that he asked a woman with whom he had an affair to seek an abortion, despite being a staunch opponent of Roe v. Wade.

The scandal represents one more headache for Republicans, and one more opportunity for Democrats. And it comes at a pivotal moment for both parties in Pennsylvania, where the state Supreme Court recently struck down gerrymandered districts drawn to Republicans’ advantage.

Whoever wins this race will be the last person to represent the 18th district as it had been conceived up until this point. Both parties are now poised to fight hard to make sure their candidate comes out on top.