Who says he'll even be in the debates?
The polls.
I believe it's the polls in a couple months time (or maybe later) that count, not the polls now. We'll see where Trump is standing then.
The first debate is August 6th. Fox says they'll use the five most recent national polls, but the thinking is that they probably won't count internet or robo-pollsters. Given that, "the five most recent national polls" will probably include polls that begin by mid-July or so. So the polls that "count" towards scoring an invitation are probably going to start coming up within 3 weeks.
Thanks for the correction. Still plenty of time for Trump's polling numbers to fall off.