I don't see how Trump could have held onto power by declaring martial law, even if his supporters had massacred Congress people. In the first place, America's top military officer, General Mark Milley, made it clear soon after the election that the first loyalty of the armed forces is to the Constitution, not to any individual. Clearly not constitutional for Trump to keep Biden out by sending a crowd of toughs against the legislature! In the second place, even if leaders of the armed forces were to support such a coup, what would be the response from the 80 million people who voted for Biden? There would have been a huge outpouring of anger, even bigger than the Black Lives Matter protests last year... The result would be comparable to what happened in Venezuela in 2002, when a rightwing coup régime was brought down in a couple of days.