If we get to TIS (tanks in the streets) it’s too late. If the government is willing to blast civilians with Military grade weapons used by the standing army to kill citizens within United States territory, then they must be resisted by armed force. They wouldn’t then deserve to be the government of a democracy anymore. At that point it would have gone beyond checks and balances.
If that happened, it wouldn’t happen in a vacuum, national guard units and reserves would in theory rebel and you would see a splintering, but you would also see hardware seized by both sides.
And the collolary to what you believe is that you are already unable or unwilling to resist. If that became necessary. That’s a sad state of affairs.