Obama Adviser Looks Into Romney's "Core," Finds Nothing

What's at Mitt Romney's core? Nothing -- if you ask Obama adviser David Plouffe.

The president's political adviser made the accusation that Romney "has no core" during Sunday's Meet the Press and pointed to the former Massachusetts governor's history on gay rights as proof.

"He's moved all over the place," Plouffe said about issues ranging from climate change to gay rights. "If he thought it was good to say the sky was green and the grass was blue to win an election, he'd say it."

Plouffe said that when it came to gay rights, Romney was once more liberal than Ted Kennedy, the late liberal lion of the U.S. Senate.

"He was to the left of Ted Kennedy on gay rights issues. Now he wants to amend the constitution to prohibit gay marriage," Plouffe said, subtly reminding viewers that Romney once ran against Kennedy for his Senate seat. And during the race, Romney won the endorsement of the Log Cabin Republicans of Massachusetts that Kennedy has also sought by promising "as we seek to establish full equality for America's gay and lesbian citizens, I will provide more effective leadership than my opponent."

Romney has said he has always supported "gay rights," and that he hasn't changed, it's the definition of what it means that's changed.

Plouffe touted Obama comparatively as having "a true compass."

"What you need in that office is conviction," he said.

For his part, though, Obama has been criticized for also changing views on same-sex marriage, at least in writing. In response to a 1996 political questionnaire from an LGBT newspaper in Chicago, Obama said he supported same-sex marriage "and would fight efforts to prohibit such marriages." He was running for Illinois state senator at the time.

White House officials have said since that a staffer filled out the questionnaire, not Obama. And the president, who opposes a federal marriage ban but also does not favor same-sex marriage, has said his views on the issue are "evolving."

Visit msnbc.com for breaking news, world news, and news about the economy