The latter's a good idea either way regardless, to be honest.
In any case, however... Yeah. I share your concerns. I'm really hoping that Rubio pulls it off here, but that's hardly a given at this point. While I very highly doubt that Trump could actually win a national election (basically no minorities will vote for him, only a piddly number of women, and less than half of the white middle class unless he manages to pull an almost literal rabbit out of his hat), it's certainly a contingency we need to keep in mind either way regardless.
Best case scenario (which still sucks pretty hard, as far as I'm concerned), it turns that he was just bluffing on most of what he claims to believe, or finds himself blocked by overwhelmingly resistance in congress and the courts, and basically just winds up governing like an uncharacteristically militaristic "lame duck" democrat. Our over-seas position and credibility will undoubtedly suffer, just because of Trump's out of control mouth and uncouth image, but some variation of that's likely to happen either way regardless, simply given how the United States isn't as militarily or economically "all-powerful" as it used to be. In any eventuality, I doubt even Trump would be nuts enough to try and start another war.
Worst case scenario? Well... I'm not even really in the mood to talk about that right now. lol