Even when the Democrats were in full control of Congress and the White House in 2009-2011there were brakes with the filibuster and the Supreme Court. The big difference now is that the Democrats have gone full socialist and the radicals running the party will do anything to have single party rule and more important to suppress any opposition. Trump hatred extends to anyone who supported Trump and the radicals will seek vengeance. The cancel culture and race theory will wipe out our history and treat whites especially white males with a contempt that will rival the Nazi treatment of the Jews in the early 1930s. Talk radio will be silenced and the Internet will be censored much like in China. A social credit system again like in China will be instituted to dole out government benefits including health care. If you arent totally in line with what the government wants you to think and do...no health care for you.
The first task will be to disarm the people. That will create open and violent revolt. I could see a President Harris (Joe will be replaced in six months due to senility) order military troops to quell a rebellion. Whether US troops will open fire on civilians remains to be seen. I would expect wide spread mutiny. Gun confiscation will be the fuse that starts a civil war