I'd like to see an amendment to the Constitution that says something like this:
"No person who is a fascist shall hold any office, civil or military, under the United States or any State or territory, or shall be an elector of President or Vice President."
After the Civil War, the United States restricted former Confederates from holding office. I think the same should be done of fascists.
This is a serious proposal, by the way.
Would be very hard to define and lead to abuse in practice + demands for a ban on Communists, Islamists etc. It opens Pandoas Box to go that road. Also fundamentally undemocratic.