Romney: 'If I'm a weak front-runner,' what's Gingrich?

"If I'm a weak front-runner, what does that make Newt Gingrich? Because I'm well ahead of him. I'm happy to be solidly ahead," Romney said on "Fox and Friends."

Romney, who was celebrating his 65th birthday in Mobile, Ala., ahead of Tuesday's Southern primaries, aimed to make the case that he is steadily building the delegate lead he needs to secure the nomination.

For more on Romney's claim that he is "closing the deal" to become the Republican presidential nominee, head over to The Hill's Blog Briefing Room. And for breaking news and commentary on the 2012 Republican presidential nomination, check out The Hill's GOP12 blog.