100% our best defense is how disparate the system for voting is. With DC being an armed camp I expect they will claim the election was rigged and refuse to seat electors. however in regard to the elections themselves - if armed national guard from another state show up and say "we've been ordered
to take possession of the voting machines and ballots" it seems that Dems would respond with an appeal to SCOTUS and then SCOTUS could just sit on its hands. If they did this in a few large counties in each blue state.... who would stop them? and by then the regular military brass will be all MAGA