If we had a federal government — especially the Executive Branch — that operated within any kind of sane (constitutional) limits, we wouldn’t have to worry about this. Any president who wants to go full-dictator only has to take a very small step.
We have come to the point that the solution you seek, the some one who should do something, is looking back at you from your mirror. Same for each and every one of us. The only question is when and how?
There is no cavalry coming over the hill. Least of all crapitol hill and congress and your representative. They all are busy feathering their own nest.