Depends on what you mean by “shut him down”, I suppose. It will certainly have an impact on those low to moderate info voters who get their presidential information mostly from from the conventions, debates, tv ads and the occasional front page headline. A significant impact, in my opinion.
I have an acquaintance who is very wealthy and very very privileged. She’s a strongly right-wing on most issues (especially rich-people issues like taxes, regulation, and giving anything to poor people). She also, thanks to 30 years of non-stop derp from the RWNJs, absolutely despises and completely mistrusts Hillary Clinton. But she’s not all that informed - she doesn’t follow politics closely, and her familiarity with the primaries was an occasional news report.
Her first serious, more-than-five-minutes exposure to Trump was the convention. And all it took was actually seeing what Trump said and did there and for the week after for her to put up a FB post saying “OK, OK, I’m convinced. I still don’t like Hillary, and I still don’t trust her, but #ImWithHer.” This is a woman who has voted Republican since Reagan.
His hardcore fans are irrelevant. They’ll forgive, excuse or deny literally anything he does wrong. But there are still plenty of folks who are undecided, or are just “leaning”, without really knowing a damned thing about what’s going on. And those are the ones it would affect, I think. I mean, Trump’s craziness so far has gotten Charles Krauthammer and Bill Kristol to come out publicly against him. Seeing him meltdown on TV could certainly convince a lot of far less partisan folks to do the same
yum yum