WASHINGTON (AP) — Control of the Pennsylvania House of Representatives hangs in the balance in a special election on Tuesday in the Philadelphia suburbs. If that sounds vaguely familiar, it’s because it’s the fourth time in a year that a vacancy has put the majority up for grabs in the evenly-divided lower chamber.

Voters in the 140th state House district in Bucks County, sandwiched between Philadelphia and New Jersey, will pick a replacement for former Democratic state Rep. John Galloway, who was elected to a judgeship last year. Galloway’s departure once again deadlocked the chamber at 101-101.

The candidates vying to hand their party the critical 102nd seat for control of the House are Democrat Jim Prokopiak and Republican Candace Cabanas. Prokopiak, an attorney from Levittown, has served on the Pennsbury School Board since his election in 2021. He previously served on the Falls Township Board of Supervisors. Cabanas of Fairless Hills is a political newcomer who has worked in the home health care and hospitality industries.

In the 2022 midterm election, Democrats won a majority in the Pennsylvania House for the first time since 2010, but Republicans occupied more seats by the time the term began in January because of three vacancies that were created after the election. Democrats regained the majority last February after winning special elections to fill the three vacancies. Two additional vacancies forced another round of special elections in May where Democrats restored their slim 102-101 majority. Democrats beat back a third challenge to their majority in September after Democratic state Rep. Sara Innamorato resigned to focus on her successful bid for Allegheny County Executive.

Here’s a look at what to expect on election night:

SPECIAL ELECTION DAY

The special election for Pennsylvania state House District 140 will be held Tuesday. Polls close at 8 p.m. ET.

WHAT’S ON THE BALLOT

The Associated Press will provide coverage for one contest in the commonwealth: the special election for Pennsylvania state House District 140. Two candidates are listed on the ballot: Cabanas and Prokopiak.

WHO GETS TO VOTE

Any voter registered in Pennsylvania state House District 140 may participate in the special election.

DECISION NOTES

Pennsylvania state House District 140 is located in the southeasternmost corner of Bucks County, bounded to the east and south by the Delaware River and jabbing like a sharp elbow into the side of New Jersey, near Trenton. Democrats have fared well here in the highest-profile races of the last few years. District voters preferred President Joe Biden over former President Donald Trump in 2020, 55% to 44%. They delivered even bigger margins to Democrats in 2022. U.S. Sen. John Fetterman defeated Republican Mehmet Oz, 56% to 40%, and Gov. Josh Shapiro beat Republican Doug Mastriano by nearly 30 percentage points, carrying all 33 precincts along the way. Galloway, the former incumbent, was unopposed in his final campaign here.

Races further down the ballot do offer some clues as to how a Republican could prevail in the district, although probably on a smaller scale given the area’s voting history. Fourth-term Republican U.S. Rep. Brian Fitzpatrick carried District 140 in 2022, 51% to 48%, winning 24 of 33 precincts over his Democratic opponent. It was a narrower outcome than the 55% to 45% win he scored in his congressional district overall. His best areas, the lower portion of Middletown Township and parts of neighboring Falls Township, form what might pass as the district’s Republican base, although Democrats Fetterman and Shapiro almost completely swept the area in their races.

Lower Middletown Township is the most Republican-voting region of the district. It is represented in the state Senate by Republican Frank Farry, who carried nine of the 10 precincts in House District 140 that overlap with his own state Senate district. One of those precincts, known as “Middletown Township Lower #3,” has the distinction of being the only precinct in the district that Dr. Oz carried in his failed U.S. Senate bid.

On Tuesday night, if initial returns don’t show Republican Cabanas dominating all of Middletown as well as peeling off a significant portion of the Falls Township precincts where Fetterman and Shapiro won with their smallest margins, then there is essentially no path for her to win.

The AP does not make projections and will declare a winner only when it’s determined there is no scenario that would allow the trailing candidates to close the gap. If a race has not been called, the AP will continue to cover any newsworthy developments, such as candidate concessions or declarations of victory. In doing so, the AP will make clear that it has not yet declared a winner and explain why.

WHAT DO TURNOUT AND ADVANCE VOTE LOOK LIKE

As of Feb. 1, there were 41,190 voters registered in District 140. Of those, 50% were Democrats, 33% were Republicans and 13% were independents. Turnout in District 140’s general election in 2022 was 19,130 voters, or about 45% of registered voters at the time.

As of Thursday, 2,983 ballots were cast before Election Day, about 79% from Democrats and about 13% from Republicans. By comparison, 5,170 pre-Election Day ballots were cast in the 2022 general election in District 140, about 27% of the total vote.

HOW LONG DOES VOTE COUNTING USUALLY TAKE

The AP did not tabulate the District 140 race in the 2022 general election because the Democratic incumbent ran unopposed. However, in the three neighboring districts, all of comparable size to District 140 and also located within Bucks County, the first votes were reported at about 11:42 p.m. ET, with election night tabulation ending at about 1:14 a.m. ET. At the time tabulation stopped for the night, 89% of the vote had been tabulated in District 31 to the northwest, 97% had been tabulated in District 141 to the southwest and 93% had been tabulated in District 142 to the west.