Indiana state senators are expected to take a final, high-stakes vote on redistricting Thursday after months of pressure from President Donald Trump, and the outcome is still uncertain.

Even in the face of one-on-one pressure from the White House and violent threats against state lawmakers, many Indiana Republicans have been reluctant to back a new congressional map that would favor their party’s candidates in the 2026 elections.

Trump is asking Republican-led states to redistrict in the middle of the decade, an uncommon practice, in order to make more winnable seats for the GOP ahead of next year’s elections. Midterms tend to favor the party opposite the one in power, and Democrats are increasingly liking their odds at flipping control of the U.S. House after the results of recent high-profile elections.

In Indiana, Trump supports passage of a new map drawn up by the National Republican Redistricting Trust designed to deliver all nine of the state’s congressional districts to the GOP. Republicans currently hold seven of the nine seats.

On Wednesday night, he sharply criticized party members who didn’t want to go along with the plan, and he repeated his threat to back primary challenges for anyone who voted against it.

“If Republicans will not do what is necessary to save our Country, they will eventually lose everything to the Democrats,” Trump wrote on social media.

The new map would split the city of Indianapolis into four districts, each included with large portions of rural Indiana — three of which would stretch from the central city to the borders of nearby states. Indianapolis now makes up one congressional district long held by Democratic U.S. Rep. André Carson.

The proposed map is also designed to eliminate the district of U.S. Rep. Frank Mrvan, who represents an urban district near Chicago.

A dozen lawmakers of the 50-member state Senate have not publicly declared a stance on the new maps.

If at least four of that group side with the chamber’s 10 Democrats and 12 other Republicans who are expected to vote no, the vote would fail in a remarkable rebuke to Trump’s demand.

Supporters of the proposed map need at least 25 yes votes; a tie would be broken with Republican Lt. Gov. Micah Beckwith’s vote, who is in favor of redistricting.

In a Senate committee Monday, the redistricting legislation took its first step toward passage in a 6-3 vote, with one Republican joining the committee’s two Democrats in voting against it. However, a few of the Republican senators indicated they may vote against the bill in a final vote.

The Republican supermajority in the state House passed the proposed map last week. Twelve Republicans voted with the chamber’s 30 Democrats against the bill.

Nationally, mid-cycle redistricting so far has resulted in nine more congressional seats that Republicans believe they can win and six more congressional seats that Democrats think they can win. However, redistricting is being litigated in several states.

Texas, Missouri, Ohio and North Carolina quickly enacted new GOP-favorable maps. California voters recently approved a new map in response to Texas’ that would favor Democratic candidates, and a judge in Utah imposed new districts that could allow Democrats to win a seat, after ruling that Republican lawmakers circumvented voter-approved anti-gerrymandering standards.

Multiple Republican groups are threatening to support primary opponents of Indiana state senators who vote against redistricting. Turning Point Action pledged “congressional level spending” in state Legislature races if the redistricting measure does not pass. Trump has also vowed to endorse primary challengers of members who vote against the new map.