As GOP field shrinks, Mitt Romney keeps focus on Newt Gingrich With the Republican presidential race narrowed to four candidates, Mitt Romney cast himself on Thursday as the lone Washington outsider still competing for the nomination, saying his career in business made him better qualified than Newt Gingrich to revive the economy. The former Massachusetts governor singled out the former House speaker as emblematic of Washington insiders, mocking Gingrich for saying that he deserves credit for jobs created when he was in Congress. During President Obama's visit to Disney World on Thursday, "he may bump into Speaker Gingrich down there in Fantasyland," Romney told a few dozen supporters at a rally in a strip-mall parking lot outside his Charleston headquarters. "If you've been there too long," Romney said of Washington, "I think you get this mind-set that you're really creating the economic vitality of the nation. That's not how it happens. Romney spoke just as Texas Gov. Rick Perry was bowing out of the race and endorsing Gingrich. He took the opportunity to stress Perry's approach of presenting himself as an outsider who can shake up Washington. "When the speaker was speaker," Romney said of Gingrich, "I was working in businesses. I was trying to get my enterprises to be successful. I was helping start businesses like Staples and Bright Horizons, a new steel plant called Steel Dynamics. I know how jobs come. They don't come because of Washington. They come in some cases in spite of Washington. Romney vowed to use his private-sector background "to help get America back to work with good jobs and rising incomes." After visiting volunteers working in his campaign office, Romney was besieged by reporters asking him about Perry as he walked with his security detail to a large SUV. "Gov. Perry -- terrific guy, terrific conservative, been a great governor, was great in the race, and we're going to miss him on the stage tonight," Romney said before climbing into the back seat. Good guy. Romney's remarks came as polls show his lead over Gingrich narrowing ahead of South Carolina's Republican primary Saturday. Perry's withdrawal could heighten prospects that conservatives will coalesce behind Gingrich as Romney's lead challenger for the nomination. But at the same time, ABC was preparing to broadcast an interview with one of Gingrich's ex-wives making disparaging remarks about him, which could undercut the former speaker with the same voters. Stuart Stevens, Romney's chief campaign strategist, declined to comment on what effect Gingrich's ex-wife might have on the contest. "Not going to touch that," he said, holding his hands in the air in a gesture to show his unwillingness to discuss the topic. But Stevens spun Perry's withdrawal as a positive development, saying it would reframe the contest as "a clear choice" between Romney and three Washington insiders - Gingrich, former Pennsylvania Sen. Rick Santorum and Rep. Ron Paul of Texas. "You have only one candidate up there who is not from Washington," he said. Joining Romney at the rally - a notably small-scale affair for a big-city rally less than 48 hours from a crucial primary - were South Carolina Gov. Nikki Haley, Sen. Rob Portman of Ohio and former Minnesota Gov. Tim Pawlenty. In a rare display of his melodically challenged musical skills, Romney sang "Happy Birthday" to Haley, who he said was turning 40.