Rubio is set to give a speech in New Hampshire today in which he will blast his Republican rivals on foreign policy. This is one of things he is expected to say:
On the other side of this election is the party of Reagan, the party of strong national defense and moral clarity, yet we have Republican candidates who propose that rulers like [Syrian President Bashar al] Assad and Putin should be partners of the United States, and who have voted with Barack Obama and Harry Reid rather than with our men and women in uniform. We have isolationist candidates who are apparently more passionate about weakening our military and intelligence capabilities than about destroying our enemies.
Rubio’s reliance on the “isolationist” slur as a crutch in his disputes with Trump and Cruz is embarrassing for him, and it shows once again that he doesn’t know how to react to nationalist hawks that disagree with him on certain policies. Neither Trump nor Cruz can be successfully labeled “isolationists” since they both advocate for intervening in some parts of the world, and they can’t be portrayed as “weak” on foreign adversaries since both have gone overboard in their “bomb the hell out of them” rhetoric. The fact that Rubio would try to pin these labels on them just reminds voters how reflexively interventionist and out-of-touch he is. Rubio is doing this because he thinks he has an advantage on foreign policy, but most Republicans are unlikely to perceive Trump and Cruz the way he wants.
Rubio is trying to attack two demagogic nationalists with the rhetoric usually deployed against non-interventionists and liberals, but unlike these targets the nationalist candidates can always sound more hawkish than Rubio. Though he doesn’t realize it, Rubio’s reliable support for constant meddling in foreign conflicts makes him vulnerable to criticism from his nationalist rivals and gains him nothing with most voters that have never wanted the U.S. involved in these conflicts in the first place. As he rails against non-existent “isolationists,” he is unwittingly advertising how unpopular his particular brand of interventionist foreign policy is even among Republicans.