Voters in Allegheny County, Pa., will head to the polls Tuesday in a special election that will determine which party controls the Pennsylvania state House.

Pennsylvanians in the state’s 21st House District are choosing between Republican Erin Connolly Autenreith and Democrat Lindsay Powell, who are both running to fill the remainder of former state Rep. Sara Innamorato’s (D) term after Innamorato stepped down to run for Allegheny County executive. 

Innamorato’s resignation evenly split control of the state House, 101 to 101. Though the 21st District is Democratically friendly, Tuesday’s special election will decide whether Democrats retain their narrow edge in the state House.

Here are five things to know about the Tuesday special election:

It’s between a real estate agent and nonprofit director 

Autenreith, a real estate agent and the chair of the Shaler Township Republican Committee, is running against Powell, who is the director of workforce strategies at nonprofit InnovatePGH. Powell has previously worked for Senate Majority Leader Chuck Schumer (D-N.Y.) and House Minority Leader Hakeem Jeffries (D-N.Y.).

Autenreith was at former President Trump’s rally Jan. 6, 2021, but left before the attack on the Capitol, according to PoliticsPA

Several prominent Democrats in the state have waded into the race to back Powell, including Rep. Summer Lee (D-Pa.) — a former state representative herself who became the first Black woman to win a House seat in Pennsylvania last cycle — and Rep. Chris Deluzio (D-Pa.). The Pittsburgh Fraternal Order of Police has backed Autenreith, according to Pennsylvania Capital-Star.

Campaign filings show Powell has had a clear fundraising advantage over Autenreith: Autenreith’s campaign raised just more than $6,000 between near the end of July and early September while Powell’s campaign has raised close to $53,000.

Allegheny County went largely for Biden in 2020

Allegheny County voted for Biden by 20 points in 2020 — a higher margin than Hillary Clinton’s 16.5-point win in 2016.

Innamorato won the state House District last cycle with roughly 64 percent of the vote while Republican challenger Frank Perman received 36 percent. The district includes part of Pittsburgh in addition to Shaler, Reserve, Etna and Millvale.

It’s the third special election in less than a year that’s determining state House control

The Tuesday election marks the third time in less than a year in which Pennsylvanians have voted in a special election that determined partisan control of the state House. 

While Democrats won the state House majority last November, several retirements and the death of a member prompted several special elections in February. Democrats prevailed in all three races.

But some Pennsylvanians were forced to head back to the polls in May following the resignation of former state Rep. Michael Zabel (D), who stepped down amid sexual harassment allegations. Democratic state Rep. Heather Boyd (D) won the Delaware County seat, keeping state House control in Democratic hands.

Innamorato announced in July after winning the Democratic nomination for Allegheny County executive that she was stepping down, prompting a third special election. She goes head-to-head with Republican Joe Rockey this fall.

One variable that has added some uncertainty to the race, however, is the timing of the election. Voters may be less tuned in to races in September, compared to attention around November elections.

Election will determine if Gov. Shapiro has at least one chamber he can work with

Despite the expectation that Democrats will keep the 21st House District seat Tuesday, the election is critical for the party given it will offer Gov. Josh Shapiro (D) at least one legislative chamber he can work with. 

Republicans control the state Senate by a 28-22 margin while state House Democrats retained a narrow 102-101 margin of control before Innamorato’s resignation. 

Race underscores the importance of Pennsylvania as one of a handful of swing states 

Though the election has immediate local implications, the state House race is also important nationally given state legislatures’ decisive roles on issues like certifying the 2020 election and the battle over abortion access.

The issue of abortion access loomed over the May special election between Boyd and Republican Katie Ford. That race came close to a year after the GOP-led state Legislature passed a proposed constitutional amendment that taxpayer-funded abortion rights were not granted under the state’s Constitution.

Republicans would have needed to pass the amendment again in the state Legislature’s current session before it could have made its way in front of voters on the ballot, but Democrats’ win in May halted the effort. 

The issue of contesting the 2020 election results was also a salient one in Pennsylvania. Several GOP state legislators were a part of an effort to try to get the 2020 election results overturned in the state following President Biden’s win, though the effort did not succeed, according to NBC10 Philadelphia.