Well, they're "duly elected" and so the only way to remove them would be expulsion by a 2/3 vote for either their failure to meet the constitutional qualifications for office, which would be age, citizenship or non-inhabitancy in the State they represent, or for disloyalty to the Government, as far as I know.

And while they definitely qualify via disloyalty, at least, as long as the Dems control the House, that'll never happen.