While we're busy beating the tar out of John McCain over McCain-Feingold, it's only fair to remember that Mitt Romney, who has vowed to fight for the repeal of McCain-Feingold if elected, used to sing a very different tune on campaign finance:
Big surprise. I know.
It's also worth noting that what Mr. Romney is suggesting here, campaign spending limits (as opposed to contribution limits) is far more unconstitutional than the already anti-constitutional McCain-Feingold. Even the Supreme Court that upheld contribution limits understood that restricting what candidates spend on campaigns would be a blatant violation of the First Amendment.
Mr. Romney, apparently, has (or, at least, had) no such understanding of the Constitution.