It’s easy to do that when she will suffer no consequences whatsoever for it. He’s not sacrificing her to save himself, he’s using a convenient excuse whereby the member of the household who has some nominal expectation of impartiality and civic support keeps their hands clean because their spouse has apparently have zero implications for their impartiality or ethics (see Thomas, Ginni).
“Throw someone under the bus” implies the other person going under the bus is bad for them and you’re doing it so they receive the harm instead of you. If someone says “hey, who shit in my flower bed” and you blame your dog, the dog isn’t going to suffer any consequences. I think Alito’s wife probably thinks he’s outplayed the haters, not that he’s harmed her to save himself, because nothing at all will happen to her.