Well in that country pretty much everything was tried except for civil war, but because a much more powerful neighbor actively supported the autocrat, everyone saw it's futile.

In US case I think the most efficient way would is to start petitions to impeach your representative for their lack of fight. Elected officials are extremely sensitive to not being re-elected.

I think US is still pretty far from the point where the only option is violence. In my previous country that is the only option left unfortunately.