A state senator has thwarted a GOP effort to lock down all of Nebraska's electoral votes for Trump

A Republican effort to lock down all of Nebraska's electoral votes for former President Donald Trump appeared doomed Monday when a state lawmaker denied backers his crucial support for the move.

GOP Sen. Mike McDonnell of Omaha said in a statement that he opposes awarding Nebraska's five electoral votes on a winner-take-all basis, like 48 other states do. Nebraska and Maine give two electoral votes to the candidate who wins statewide and one vote to the winner in each congressional district.

McDonnell's position means Republicans don't have the two-thirds majority they'd need in Nebraska's unique, one-chamber Legislature to pull off a change ahead of the Nov. 5 election.

Here's a look at why Trump's allies were pushing for the change, what it would have taken to succeed and why a single state lawmaker is in the national spotlight.