Two weeks ago a meeting of four noted anti-Trump ex-Republicans met in the home of semi-lunatic Tucker Carlson. They came up with the idea of launching a new political movement around the issue of anti-war.
A chief idea was that this new party would have a minimalist program concerned only with foreign policy; and so, the anti-war right and the anti-war left would be able to unite around it.
You can watch an excited discussion of it here:
https://www.youtube.com/watch?v=s5r5U-2pENw . [Beware of bizarre advertisement in the middle.]