SARASOTA, Fla. - With recession fears growing, Mitt Romney’s latest television ad is part resume, part resolve. And all reassurance. "I know how America works because I spent my life in the real economy," says the man who made millions as a venture capitalist. "My plan will make America strong." No mention of John McCain, Rudy Giuliani or Mike Huckabee, Republican presidential rivals whose campaign credentials lean heavily on government service. The point is unmistakable, all the same. The ad is the most visible element of Romney’s strategy for the final week of the Florida primary. After a series of...