Cities in a new red state country will be a problem but not an insurmountable problem. Martial law for a few years then let them up slowly.
If I were doing it I would close any university with the slightest hint of leftism and build new universities from scratch—likewise for any media outlets...
Yes, many , including national voter numbers have been brainwashed that if a state is blue it is the whole state, when in fact it is just a few high density sardine pack towns or coty counties that are blue.
Seige works.
And the polititions know this, if they push hard enough then those tiny little county islands of blue are all they have to “rule over”
Blessings.