NATIONAL HARBOR, Md.-In his first public speech since losing the presidential election, a humbled Mitt Romney addressed a crowd of conservatives who supported his 2012 campaign and told them his loss "prepared" them for "larger victories" ahead.

Just over four months since his defeat, he said it was up to the group at the conservative confab to "make sure that we learn from my mistakes… and from our mistakes, so that we can win the victories this people and this nation depend upon." Romney told the supportive crowd at the Conservative Political Action Conference that he "left the race disappointed."

Live Updates: CPAC 2013

The former GOP nominee has kept a low profile since his loss in November and said he is "sorry that I will not be your president," but he assured the group of conservatives he will be their "co-worker and I will work shoulder to shoulder with you."

"Each of us in our own way will have to step up and meet our responsibility," Romney, dressed in a blue tie, said. "In the end, we will win just as we have won before, and for the same reason: because our cause is right…and just."

Image credit: Manuel Balce Ceneta/AP Photo

Left undiscussed by Romney were any hint of why he thought he lost the race, what role he wants to play in the party or any of the big hot button issues of the day like the federal budget, sequestration or gay marriage.

Romney noted, as he did in a recent Fox News interview, that "as someone who just lost the last election, I'm probably not the best person to chart the course for the next election," but he did offer some advice, saying the country's 30 Republican governors should be watched closely. He specifically called out two of them who weren't invited to the conference: New Jersey Gov. Chris Christie and Virginia Gov. Bob McDonnell.

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"They are winning elections, but more importantly, they are solving problems," Romney said. "We need the ideas and leadership of each of these governors. We particularly need to hear from the governors of the blue and purple states, like Bob McDonnell, Scott Walker, John Kasich, Susanna Martinez, Chris Christie, and Brian Sandoval because their states are among those we must win to take the Senate and the White House."

Romney was greeted by a standing ovation when he took the stage to his familiar presidential campaign theme music, Kid Rock's "Born Free," and the mention of the governors were also greeted by cheers.

As he often did on the campaign trail, he urged those gathered - and the nation - to be optimistic.

Transcript: Romney Addresses CPAC

"It's fashionable in some circles to be pessimistic about America, about conservative solutions, about the Republican Party," Romney said. "I utterly reject that pessimism. We may not have carried the day last November 7th, but we haven't lost the country we love, and we haven't lost our way."

This wasn't the first time Romney had spoken to the group. Last year, Romney received some ribbing from both sides of the aisle when he described himself as "a severely conservative Republican governor." And in 2008, it was at CPAC he decided to drop out of that year's Republican primary.