Via First Read, I see Obama's taken Tom Friedman to heart and begun using the gas tax holiday to tie Hillary to McCain:

Meanwhile, Obama once again stated his opposition to such a holiday while also campaigning in Indiana. "This isn’t a real solution. This is a gimmick," he said. "And this is what Washington does whenever there’s a big problem. They pretend that they’re solving it to try to get though a political season but they don’t really solve it. And unfortunately, after John McCain made the proposal, I guess Sen. Clinton thought it was gonna poll well, so she said, 'Me too, I’ll do the same thing.’ and so now it’s the McCain-Clinton proposal to suspend the gas tax.

He then said, "You know people are more concerned about looking good for the cameras and for politics than they are at actually solving problems. You remember when George Bush five years ago put up a big sign in front of an aircraft carrier saying ‘Mission accomplished’ in Iraq. I’m sure they thought that was good politics. Except five years later we’re still in this war in Iraq."

It's sounds even more effective than I imagined it would. (Note the implicit tying of McCain and Hillary to the war, too.)

Update: Key typo corrected.

--Noam Scheiber