A mas­sive vote swing against Don­ald Trump and the Repub­li­cans in west­ern Penn­syl­va­nia has put the par­ty in jeop­ardy of los­ing a ger­ry­man­dered dis­trict it has pre­vi­ous­ly had no trou­ble win­ning to a resur­gent Demo­c­ra­t­ic Par­ty hun­gry for more spe­cial elec­tion vic­to­ries ahead of the 2018 midterms.

With 99% of the vote count­ed, Demo­c­ra­t­ic con­gres­sion­al hope­ful Conor Lamb — a for­mer U.S. Marine Corps offi­cer and Assis­tant Unit­ed States Dis­trict Attor­ney — had an extreme­ly slim lead over Repub­li­can oppo­nent Rick Sac­cone. Over 200,000 bal­lots have been cast in the con­test thus far, and the two can­di­dates are vir­tu­al­ly tied with only a few bal­lots left to count — most of them absen­tee ballots.

As of 7:50 PM Pacif­ic Time, results were:

• Demo­c­ra­t­ic can­di­date Conor Lamb: 49.87% (107,556 votes)
• Repub­li­can can­di­date Rick Sac­cone: 49.52% (106,801 votes)
• Lib­er­tar­i­an can­di­date Drew Gray Miller: 0.61% (1,309 votes)

On CNN, a top elec­tions offi­cial from Wash­ing­ton Coun­ty called in live not long ago to report fresh num­bers, which (once incor­po­rat­ed into the over­all num­bers) tem­porar­i­ly cut Lam­b’s lead to just nine­ty-five votes overall.

That’s a gap in the dou­ble digits!

There are four coun­ties with precincts in Penn­syl­va­ni­a’s 18th Dis­trict. Three of them are back­ing Rick Sac­cone, while the fourth — Alleghe­ny — is back­ing Conor Lamb. That’s his strong­hold, and his sup­port there has been the key to his per­for­mance so far. Alleghe­ny is the state’s sec­ond largest coun­ty over­all; its coun­ty seat is Pitts­burgh. Offi­cials there just fin­ished count­ing absen­tee and pro­vi­sion­al bal­lots, and the results gave a sig­nif­i­cant boost to Conor Lamb.

Not count­ing the just tal­lied absen­tee bal­lots, Lamb has a healthy 57.10% of the vote in Alleghe­ny Coun­ty. It’s that strong show­ing that has allowed him to main­tain a lead over Sac­cone for much of the night. In Wash­ing­ton Coun­ty, he has 46.30%, in West­more­land Coun­ty, he has 42.25%, and in Greene Coun­ty, he has 41.33%.

The 18th Dis­trict will look very dif­fer­ent in just a few months due to court-ordered changes to Penn­syl­va­ni­a’s con­gres­sion­al dis­trict maps. (Penn­syl­va­ni­a’s Supreme Court ruled not long ago that the cur­rent map is an uncon­sti­tu­tion­al gerrymander).

Regard­less of who wins, this is already a dis­as­trous result for Don­ald Trump and the Repub­li­can Par­ty. Trump eas­i­ly won this dis­trict in 2016 by a mar­gin of twen­ty points. A year and a half lat­er, it’s on the verge of being lost to the Democrats.

UPDATE, 8:13 PM: The offi­cial count has been adjust­ed to reflect the absen­tee bal­lots from Alleghe­ny Coun­ty. These are now the cur­rent numbers.

• Demo­c­ra­t­ic can­di­date Conor Lamb: 49.89% (111,875 votes)
• Repub­li­can can­di­date Rick Sac­cone: 49.51% (111,028 votes)
• Lib­er­tar­i­an can­di­date Drew Gray Miller: 0.6% (1,351 votes)

This is a devel­op­ing sto­ry and we will con­tin­ue to post updates.