If McCain wants to mock Obama, perhaps he should pick a topic in which a) Obama is mistaken; and b) McCain knows what he's talking about.
McCain in A Glass House
Washington Post columnist George F. Will bitch slaps John McCain
“Well, you know who’s thrilled that Nader is back in the race? John McCain. He’s not the oldest guy anymore.” –Jay Leno
“But seriously how about that John McCain? John McCain looks like a guy whose head you can barely see over the steering wheel. … John McCain looks like the guy who thinks the nurses are stealing his stuff. ‘Dad, why would they take your socks? It doesn’t make sense.’” –David Letterman
“The New York Times printed a story that said … in John McCain’s last campaign in 2000, he was apparently acting so sprung on a lobbyist lady that his staff had to cockblock the senior citizen from Arizona from sweeping this chick right off her feet and onto his motorized shopping cart. … John McCain’s pick-up line is, ‘Did you know that 150 is the new 130?’” –Bill Maher
“I like that John McCain. He looks like a guy who gets tickets for mowing under the influence. He looks like a guy with a collection of movies he bought at the car wash. He looks like a guy on the beach with a metal detector. He looks like the guy who is still confused by the phone answering machine: ‘Hello, is that - hello, is that you? Larry, Larry, hello?’ He looks like the guy who calls his grandson when he screws up the remote: ‘Well, now all the shows are in Spanish. What am I going to do, hello?’” –David Letterman