Since most Americans last voted for Congress, thousands of people have been added to certain voting districts — and subtracted from others — under new political maps enacted following court rulings.

The sum of that redistricting math, assuming no major political shift in either major party’s direction, figures to provide at least a one-seat gain for Republicans in November’s U.S. House elections. But that equation could flip to Democrats’ favor depending on what happens in an ongoing effort to reshape New York’s congressional districts.

House boundaries redrawn before the 2022 elections based on the last decennial census have been redrawn again ahead of the 2024 elections in Alabama, Georgia, Louisiana and North Carolina. New York could be next. A bipartisan commission is to release a revised plan for New York’s districts by Feb. 28.

Republicans hold a narrow 219-213 House majority over Democrats, with vacancies in three seats previously held by the GOP. A special election for one of those — to replace ousted Rep. George Santos of New York — will be held Feb. 13.

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Here’s a look at how voting districts have changed — or could change — before the November elections and what affect that could have on the battle for control of Congress.

SOUTHERN SWINGS

A U.S. Supreme Court ruling last June about minority voting rights paved the way for new districts in Alabama and Louisiana. In each state, the result is that Black voters will have a better opportunity to elect the candidate of their choice in two congressional districts instead of one. Democrats are expected to gain one seat in Alabama and one more in Louisiana in the November elections.

A similar court ruling also forced the Republican-led General Assembly to redraw districts in Georgia. But the new map there isn’t expected to change the state’s proportion of nine Republican and five Democratic representatives.

Democratic gains in Alabama and Louisiana are likely to be offset in North Carolina, where Republicans could win at least three additional seats under revised districts. The Republican-led General Assembly in October approved a more GOP-friendly map after a new Republican majority of the state Supreme Court reversed decisions by the previously Democratic-majority court that had led to districts won by seven Democrats and seven Republicans in the 2022 elections.

NEW YORK’S UNCERTAINTY

The Republicans’ slight edge from redistricting changes made so far could be wiped out and transformed into a small Democratic advantage if new House districts are adopted in New York.

After a bipartisan commission failed to agree on districts based on the 2020 census, the Democratic-led New York Legislature passed a plan that got struck down in court as a partisan gerrymander. The courts then imposed districts for the 2022 elections, which resulted in a fairly close split of 15 Democrats and 11 Republicans.

But more litigation ensued, and the state’s highest court ordered the bipartisan commission to make another attempt at new districts. The commission has until the end of this month to submit a plan to the Legislature, which could approve it or reject it and instead pass its own redistricting plan. Either scenario opens the potential for Democrats to gain multiple seats.

WHAT ABOUT OTHER STATES?

Redistricting litigation also is ongoing in several other states, but none seem as likely as New York to affect the 2024 elections.

Perhaps the most notable is Florida, where a trial judge in September ruled that U.S. House districts pushed by Republican Gov. Ron DeSantis violated the state constitution by diminishing the ability of Black voters in northern Florida to elect the candidate of their choice. A state appeals court reversed that ruling in December.

The Florida Supreme Court has agreed to consider the case but has set a briefing schedule for attorneys that makes it unlikely for the case to be decided by the April qualifying period for candidates to appear on the primary ballot.

Litigation over congressional districts also is lingering in Arkansas, South Carolina, Tennessee, Texas, Utah and Wisconsin.

WILL NEW DISTRICTS MAKE A DIFFERENCE?

Redistricting changes since the 2022 elections could help Democrats or Republicans win control of Congress because “it’s a very closely contested congressional map, and every seat or two matters,” said Chris Warshaw, a political science professor at George Washington University who focuses on redistricting.

But other factors are likely to play a bigger role, Warshaw said. Voting patterns show a strong correlation between presidential and congressional elections, meaning whichever party wins the presidency has a good chance of also winning the House. Voters’ perceptions about the economy and other issues also matter. And retirements could put certain House seats into play that otherwise may have been won by incumbents.

The reshaping of voting districts matters, but doesn’t necessarily pre-determine the outcome of elections.

“Redistricting can help create a stronger base for candidates to run their campaigns on,” said Jeffrey Wice, director of the New York Law School’s Census and Redistricting Institute. “But the candidates have to perform, and the issues have to work in their favor.”