A Republican effort to lock down all of Nebraska's electoral votes for former President Donald Trump appears doomed because one state lawmaker won't give backers his crucial support.

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.

Here's a look at why Donald 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.