Newt Gingrich says he's staying in the Republican presidential nominating contest.
The former House speaker is struggling to forge a comeback after big back-to-back losses to Romney in Saturday's Nevada caucuses and Florida's primary four days earlier.
Romney vowed to stay in the race all the way to the party's nominating convention in Florida this summer.
Gingrich waged a limited campaign in Nevada, with just a handful of events and no TV ads.
He needs to forge a breakthrough as the race turns to a string of states friendly to Romney, including Colorado and Minnesota on Tuesday and Michigan, where Romney grew up, on Feb. 28.
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