What a Romney vs. McCain battle may come down to? From the Washington Post:

Romney, who plans to focus on economic issues, also took aim at McCain on “Fox News Sunday,” saying his own experience and business background can fix both the ailing economy and a politically paralyzed Washington. “If people want somebody who has been in Washington all their life and understands Washington’s ways and has been part of the Washington scene for a quarter of a century, then John McCain will be their person,” he said. McCain, in an interview with CNN, dismissed questions about the breadth and depth of his support. “I got more votes than anybody else, and it says that I got it from across the spectrum from all over the state,” he said.