How the Republicans will become more moderate...

[Warpy]

4. The various factions will keep spinning more and more into lunacy

Unless they are purged out of the party, turning the party back into a minority Hamiltonian party with the lunatics creating their own impotent splinter parties, the lunacy will tear them apart and they will go the way of the Federalist Party and the Whigs before them, sputtering on for a few years as a regional party but not fielding presidential candidates because none will get a majority of votes from feuding lunatics.

Once a Hamiltonian party begins to die, the Hamiltonian conservatives flood into the Democratic Party. The new second party is generally a group of progressives who coalesce around one issue. For the Republicans, that issue was ending slavery. Once that was accomplished, apathy set in and the Hamiltonians took it over.