A pressure campaign from Donald Trump and Republican allies to change Nebraska election law was dealt a significant setback on Monday as a pivotal Omaha state senator said he would not support a last-ditch effort to overturn a 30-year law that awards electoral votes by congressional district rather than statewide winner-take-all.

State Sen. Mike McDonnell, a former Democrat who joined the GOP earlier this year, said in a statement Monday that he would not vote to change the law in Nebraska before the November election.

“After deep consideration, it is clear to me that right now, 43 days from Election Day, is not the moment to make this change,” McDonnell said. “I have notified Governor (Jim) Pillen that I will not change my long-held position and will oppose any attempted changes to our electoral college system before the 2024 election.”

McDonnell was seen as one of the last best hopes from Republicans to change the law before November. He made clear that he had no interest in supporting a change so close to the election.

“Nebraska voters, not politicians of either party, should have the final say on how we pick a President,” McDonnell said. “I want to thank the voters who reached out to me for engaging in democracy and for showing America who Nebraskans are – fiercely independent, filled with pride about our great city of Omaha, and deeply devoted to the promise of American democracy.”

The fight over a single electoral vote from Nebraska’s 2nd Congressional District, which has become known as Omaha’s blue dot, has emerged as a symbol of just how close the race between Trump and Kamala Harris has become.

Even if Harris won the “blue wall” states of Wisconsin, Michigan and Pennsylvania, but carried no other key battlegrounds, she would still need the electoral vote from Nebraska’s 2nd District to secure the 270 electoral votes needed to win the White House.

Trump believes he will win four electoral votes from Nebraska, but it’s the fifth one that he has been increasingly fretting about – leading him and his Republican allies to mount a late effort to try and change state election law only weeks before ballots are cast. He called into a meeting of state senators last week, urging them to change the election law before November.

Trump won all five of Nebraska’s electoral votes in 2016, but won only four in 2020, with Joe Biden carrying the Omaha-area seat. The Harris campaign is spending millions to try and win that sole electoral vote again, with a grassroots effort playing out in front yards across Omaha featuring yard signs with blue dots, a hopeful symbol for Democrats in a sea of Nebraska red.

Nebraska Democratic chairwoman Jane Kleeb praised McDonnell’s decision Monday.

“Nebraska has a long and proud tradition of independence and our electoral system reflects that by ensuring that the outcome of our elections truly represents the will of the people without interference,” Kleeb said in a statement to CNN. “Senator McDonnell is standing strong against tremendous pressure from out-of-state interests to protect Nebraskans’ voice in our democracy.”

Pillen, the state’s Republican governor, has said he was still prepared to convene a special session of the Nebraska Legislature before the November election to change the law, but he would only do so if there was sufficient support. An effort failed earlier this year to change the law that is unique to only Nebraska and Maine.

McDonnell’s statement Monday seemed to close the door on the issue this year, officials said.

Neither Pillen nor the Trump campaign immediately responded to a request for comment.