Well, I think some of that is certainly possible, but I think we're allowing our nightmares to get the best of us. We have to remember a couple of things that would drastically harm Trump's ability to do certain things:
1. If Trump is out, Republicans cannot help him scorch the Earth. He may be leaving, but they aren't. If Trump is setting fire to the Lincoln Bedroom and forcing himself to be carried out by the secret service or puts tanks in front of polling places, the Republicans will have to live with those images for decades. It would put nearly every Republican politician in danger for the near future because it wouldn't just represent Trump - it would represent *them*. I think that's part of the reason why Gore and Hillary didn't put up more of a fight than they did - it would reflect poorly on Democrats to do so. So while, yes, Trump himself could potentially throw a fit, he wouldn't get support from anyone that wants to be in politics in 2021 and beyond.
That also might include his children. If Ivanka or Don Jr. or Eric Trump want to be in politics, they can't be involved with a guy who threw the world's biggest hissy fit. Same with Jared Kushner. Trump can throw a temper tantrum, but it would tarnish the Trump name forever. There's a really good chance that Trump's too narcissistic to care about his kids, but if they're fighting on it (because, again, they might want to have lives in the United States going forward), then it makes it harder.
Also remember that Trump's approval rating is hovering around 40%. I think we like to think of Trump's MAGA people as all being indoctrinated wackos who worship him, but that number isn't anywhere near that 40%. People support Trump because he's good for the economy or whatever - and setting fire to the country on his way out isn't going to be good for the economy. Yes, you'd absolutely get white supremacists and evangelicals marching on behalf of Trump, but how many people is that in reality?
2. Trump's own incompetence. People see Trump as this dictator figure who will pull off a suppression campaign with military precision. But look at his presidency and tell me where he's shown any ability to pull that off. He had a chance to do it in 2018 as a trial run, and the Republicans lost big. His government, despite having control of the House and Senate for the first two years of his presidency, passed nothing. He didn't repeal or replace Obamacare. He didn't build a beautiful wall and Mexico didn't pay for it. And even though it would've benefited him in every way to deal with the pandemic effectively, he botched that too.
Even when you look at his criminal enterprises, he's inefficient and sloppy. He didn't win on Russia and Ukraine because the Democrats couldn't prove it - he won on technicalities. He's winning on tax returns because of technicalities.
Trump doesn't know what he's doing and the people around him don't know what they're doing. Trump might actively want to send the military to polling places, but he's just as likely to send them to the wrong polling locations or the wrong states entirely. Nothing he's done so far has indicated that anyone in his administration is capable of pulling off a successful voter suppression organization, especially if he's lost support from the party. And with the electoral map looking the way it is, he'll need to pull off something that he's just not capable of pulling off in my opinion.
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All that being said, Biden's team needs to keep up enthusiasm and do everything in his power to get people out voting early and voting in person. There's plenty of time to organize efforts at a community level. If people need to plan ahead, they can plan ahead. How people can find time between the opening of early voting and the close of it. How people can get their mail in ballots in quickly and efficiently. There's tons of time to be working out kinks, and they know the Republican playbook.
With the map the way it is, if Trump is able to pull off a suppression campaign and win, Biden is going to have plenty of share of the blame because there's ways around everything Trump would try.