WASHINGTON (AP) — House Republicans’ majority could tighten by another vote after Tuesday’s special congressional election in Buffalo — at least, temporarily.

Voters are choosing a replacement for Democrat Brian Higgins, a longtime House member who cited the “slow and frustrating” pace of Congress before resigning in February. Democrats have a long record of success in the 26th Congressional District, and their nominee is highly favored to win on Tuesday.

Rather than holding a traditional primary, local party officials handpick the nominees in New York special elections for Congress. Democrats chose Buffalo state Sen. Tim Kennedy, while Republicans nominated West Seneca Town Supervisor Gary Dickson.

After a messy redistricting process in 2022, New York just recently approved new congressional maps, which will go into effect for the 2024 election. For now, New York is filling Higgins’ vacancy under the old congressional lines. However, the 26th District changes very little under the revised maps, which means whoever wins the special election to fill the remainder of Higgins’ term will face a similar electorate in November.

A Democratic victory would shrink Republicans’ 218-212 majority by one member — but not necessarily for long. Three special elections in previously Republican-held districts are on the calendar before the end of June.

Here’s a look at what to expect on Tuesday:

SPECIAL ELECTION DAY

The congressional district election will be held on Tuesday. Polls close at 9 p.m. ET.

WHAT’S ON THE BALLOT

for the special election in New York’s 26th Congressional District. Kennedy’s name appears on the ballot under the Democratic Party and the Working Families Party. Dickson appears as the nominee for the Republican and Conservative parties.

WHO GETS TO VOTE

Any voter registered in New York’s 26th Congressional District may participate in this special election.

DECISION NOTES

New York’s 26th runs along the Niagara River, which separates western New York from Canada. Most of the Republican vote in the district stems from the area that falls in Niagara County, at its northern tip. However, that’s the least populous portion of the district. Most of the votes come from the southern part of the district in Erie County, which leans heavily toward Democrats.

Democrats have been successful in the congressional district in recent elections. Higgins represented a House seat in Buffalo for two decades, and Joe Biden carried the district by double digits in 2020 when he defeated President Donald Trump.

For lots of voters in the congressional district, the two nominees will be familiar names. For over a decade, Kennedy has represented Buffalo in the state Senate in a district that overlaps with the 26th Congressional District. Dickson, meanwhile, appeared on the ballot in West Seneca in 2019 and 2023, though in a much smaller election for town supervisor.

Dickson said he believes his path to victory depends on not only consolidating votes in the northern portion of the district but also winning over working-class voters in the southeast corner and flipping suburban voters who are frustrated with high taxes in Amherst. As of the latest filing deadline on April 10, Kennedy’s campaign had spent 50 times more on the race than Dickson’s had.

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.

A recount is required if a candidate wins by 20 votes or fewer or by less than half a percentage point. The AP may declare a winner in a race that is eligible for a recount if it can determine the lead is too large for a recount or legal challenge to change the outcome.

WHAT DO TURNOUT AND ADVANCE VOTE LOOK LIKE

As of Nov. 1, there were 512,774 registered voters in New York’s 26th Congressional District. Of those, nearly 50% were Democrats and 22% were Republicans. The last race for the district took place in November 2022. At the time, 48% of registered voters turned out.

But there’s been another House special election in New York more recently, when Democrat Tom Suozzi replaced Republican George Santos on Long Island in February. As of Nov. 1, there were more than 570,000 registered voters in the 3rd District, and about 30% voted in the special election.

Santos had won office in what had been a reliably Democratic district partly by falsely portraying himself as an American success story — a son of working-class immigrants who made himself into a wealthy Wall Street dealmaker. But many elements of Santos’ life story were later exposed as fabrications, and he was indicted on multiple charges including allegations he stole money from Republican donors. He has pleaded not guilty.

Ahead of Tuesday’s special election, just over 8,700 early votes had been cast by April 23. Nearly 69% of those early votes came from registered Democrats, while 19% came from Republicans.