I think he said he was in such a narcissistic rage over having been de-platformed in the first place, he did a thanks-but-no-thanks flounce. If/when he gets the nomination, I'm guessing he'll back back.
Trying not to get my hopes up, yet again, that he's going down, but it's hard to stay cynical at the moment. If they're doing it, they'd better get moving.
On a side note, I've been listening to Nicolle Wallace's show as a podcast and am really liking it - enough that I've almost forgiven her for Bush, McCain, Palin.