08/31/2012 02:27 pm ET

Newt Gingrich Repeatedly Trash-Talked Mitt Romney Before Supporting Him In RNC Speech (VIDEO)

GOP presidential nominee Mitt Romney isn't the only influential Republican politician who can be accused of flip-flopping. He can now count former opponent Newt Gingrich as his ally in contradicting past statements.

Over the course of many months earlier this year, former House Speaker Gingrich had no reservations about attacking Romney's character and record. He called Romney "the weakest Republican frontrunner" in almost 100 years, said Romneycare used taxpayers' money to fund abortions, and outright called Romney a "liar" during an appearance on CBS's "The Early Show" in January.

"Talk about every possible example of what we don't want in a general election candidate," Gingrich told a crowd during a campaign rally in Las Vegas in early February.

But on Thursday at the Republican National Convention in Tampa, Gingrich praised Romney's "bold, visionary leadership" and even compared him to beloved former President Ronald Reagan.

In some ways, this is just politics as usual, and of course Gingrich was competing with Romney for the Republican presidential nomination when he made most of these attacks. But which Gingrich sounds more sincere: The one who is criticizing Romney's record or the one who is blandly endorsing Romney at the party's national convention?

Click the video above to decide for yourself.