This really isn't satire. What is depicted is realism. Cindy was prescription drug dependent and stole from a charity she worked for. Bush's picture over the fireplace is believeable, since McCain supports the Bush administration's agenda, and advocating for torture (he was against it before he was for it) is unConstitutional. And finally, McCain is the oldest candidate to run for president. (OK, he doesn't need a walker--but he could use a geography lesson.)
Satire by definition is A work, as a novel, play, or cartoon that exposes folly by the use of humor or irony.
The cover depicted by the New Yorker showed Sen. and Mrs. Obama as the wingnuts see him--and it is folly (satire), since they are not at all what was lampooned--but what the righties think they are, and probably worse.
The McCains, OTOH, are/were (Cindy has recovered from her drug addiction) exactly--except for the walker--as shown.