Former GOP presidential candidate Rick Santorum gave a signal to social conservatives on Saturday: Mitt Romney's "message is sound. It's solid."

"He hit the points," Santorum said of his one-time rival while at the annual Faith & Freedom Conference and Strategy Briefing in Washington, D.C. "I've talked to Governor Romney, and I have no doubt -- and I mean this in all sincerity -- I have no doubt he understands the centrality of family. He understands the importance of family for our culture, for our economy, and for our future."

Santorum received a standing ovation at the conference, which attracted 1,500 attendees, including political figures and faith leaders, organizers said. Romney was received with less hearty applause, though supporters held pro-Romney signs before his speech.

Santorum, a former U.S. senator from Pennsylvania and a favorite of social conservatives, told attendees that he "will be working with" Romney, his former opponent in the race for the Republican presidential nomination.

Santorum's endorsement of Romney came a dozen paragraphs into a late-night e-mail sent to supporters in early May and was seen as tepid.

"Governor Romney will be that nominee and he has my endorsement and support to win this the most critical election of our lifetime," he wrote.

Prior to that message, he avoided using the word "endorsement" to describe his acknowledgement that Romney will be "the person that's going against Barack Obama."

"You can call it whatever you want," he said on CNN's "Piers Morgan Tonight" in April.

On Saturday, Santorum's praise was warm.

"The concern I had -- I did, I was very frank about it -- was that Governor Romney would track to the middle as so many Republican candidates have done, but I'm not seeing that," Santorum said. "I'm seeing him stand by those convictions that he articulated in the primaries and I'm hopeful."

Santorum took to the podium about a half hour after Romney addressed the crowd by satellite from Pennsylvania, where he is on day two of a multi-state bus tour.

Romney dropped Santorum's name in his remarks, in which he focused on several anchors in his life, including family.

As he has before, Romney pointed to a Brookings Institution study that highlighted how marriage, education and work are factors for an individual to stay out of poverty - a mantra often advanced by Santorum

"We're going to help Governor Romney. Governor Romney's speech was right on," Santorum said after Romney's remarks. "And not just because he quoted me."