A Nebraska Republican state lawmaker said Monday that he remains opposed to switching how the state allocates its electoral votes, effectively blocking a bid by President Donald Trump and his allies to change the system in a bid for an extra electoral vote this fall.

Trump allies have pushed for a special legislative session intended for the Republican-controlled legislature to change Nebraska to a winner-take-all system instead of awarding electoral votes by congressional district.

"After deep consideration, it is clear to me that right now, 43 days from Election Day, is not the moment to make this change," state Sen. Mike McDonnell wrote in a letter obtained by NBC News.

Nebraska GOP state Sen. Loren Lippincott, who sponsored the bill to move the state to a winner-take-all system, indicated Monday that McDonnell's position means a special session to move the legislation is not expected this fall.

In response to questions about McDonnell’s statement, Lippincott emailed NBC News a draft of his weekly op-ed in local newspapers, which reads: “Governor Pillen did not want to call a special session unless he had assurances from 33 senators they would vote yes on the bill. That effort did not bear fruit. There will be no special session to address Winner Take All. I will be carrying this bill, again, next legislative session.”

Lippincott clarified via email that he has not heard directly from Pillen, but he expects the governor to weigh in later this week.

McDonnell represents an Omaha-area state Senate district and is reportedly weighing a run for Omaha mayor. A former Democrat, he switched parties in April, becoming a Republican, after state Democrats censured him.

The developments appear to cap months of deliberations over whether Nebraska lawmakers could change the way the state apportions its electoral votes in a way that would benefit Trump.

Nebraska allocates its electoral votes by congressional district, and the swing district around Omaha has twice gone to Democrats in recent years, giving them one electoral vote from an otherwise ruby-red state.

But if lawmakers changed that to a winner-take-all model, Trump would be all but certain to win all of Nebraska's electoral votes.

And there's a plausible scenario in which that could determine who becomes the next president.

For example, if Vice President Kamala Harris were to win Michigan, Pennsylvania and Wisconsin but lose every other swing state, she and Trump would be tied at 269 Electoral College votes under a winner-take-all setup in Nebraska with Trump winning the state.

In that scenario, the race would be thrown to the U.S. House, where each state delegation would get one vote for president. Republicans hold a majority of delegations and are favored to retain it, even though the House majority could change hands after the November election.

However, if Nebraska did not change its apportionment mode and if Harris were to win Michigan, Pennsylvania and Wisconsin but lose every other swing state, she would win the presidential election with 270 electoral votes.

Nebraska Democrats lauded McDonnell's announcement.

“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," Nebraska Democratic Party chair Jane Kleeb said.

"Senator McDonnell is standing strong against tremendous pressure from out-of-state interests to protect Nebraskans’ voice in our democracy. In this election and those to come, Nebraskans will continue to lead the way by electing leaders at every level who stand up for the people and respect our spirit of independence," Kleeb added.

Last week, Sen Lindsey Graham, R-S.C., a Trump ally, met with Pillen and about two dozen Republican legislators to discuss how the state allocates its electoral votes, according to a source with direct knowledge of the trip.

Graham, acting on behalf of the Trump campaign, was working to encourage Pillen to call a special legislative session at which lawmakers could consider changing the state’s apportionment of electoral votes, the source told NBC News.

Proponents of the winner-take-all model would need 33 votes in the state Senate to overcome a filibuster to move forward with the change. While the state's unicameral legislature is technically nonpartisan, Republicans do have a 33-seat majority thanks to McDonnell's recent party flip. But that narrow margin means Republicans can't move forward without him.

Pillen has said that he has not yet “received the concrete and public indication that 33 [state] senators would vote” for the winner-take-all system.

State lawmakers told the Nebraska Examiner last week that they estimated that the change had the support of 30 or 31 state senators, meaning they remained two to three votes short. McDonnell had been one of them. State Sen. Merv Riepe had been thought to be another. The Washington Post reported last week that Riepe now supports the change to a winner-take-all system.

The newfound interest in Nebraska's Electoral College votes comes months after Republicans tried, and failed, to make the change this spring. Back then, a pressure campaign backed by Pillen, Trump and pro-Trump influencer Charlie Kirk fell short on procedural grounds, as it lacked support from enough senators to overcome a filibuster.

Ever since the state changed the way it allocated its Electoral College votes more than 30 years ago, lawmakers have repeatedly tried to change back to awarding all of Nebraska's votes to the statewide winner. An effort to do so passed in 1995, but it was vetoed by the governor. Another effort fell just one vote short in 2016.