Yeah, Trump's presidency is over. It's not like he can declare martial law to stop Biden's inauguration. The National Guard is busy protecting the Capitol, along with the Capitol Police and DC Metro Police. The DoD/Pentagon and Joint Chiefs have already declared they'll defend the transfer of power as a constitutionally-mandated process (not Trump the man). But if the Secret Service has been infiltrated by Trump loyalists, all bets are off. (See Indira Gandhi)

What's NOT over is the growth of right-wing domestic terrorist groups, and that they find safe haven within the GOP.