If we pull out of NATO Greenland, Iceland and a bunch of others will fall within a year. By the time they all start screaming for America to save them President Trumps term will be over and their fates will be sealed. It would not be politically correct to save them at that point.
The demonrats will get what they want, they would have denied Trump, millions will die. As Europe falls into race against race warfare and America will be seen as weak.
Bonus, we could pull all funding for anything outside of our borders and some idiot will run on the America for Americans only party and probably win.
Sounds great doesn't it (sarc).