Ugh! Here is what happens when you don’t appear to have core values and change given the circumstances. From 2003:

Governor Mitt Romney refused yesterday to endorse tax cuts at the heart of President Bush’s economic program, but he told members of the state’s congressional delegation during a private meeting he also would not oppose the cuts because he has to maintain “a solid relationship” with the White House.

Here is what he had to say about his hypocrisy:

Turning back to 2003, Romney told the man: “You see, I wasn’t a U.S. senator. I didn’t have to vote on this, didn’t get a choice to. I was running my state, so I didn’t have a comment on their position. And I said, `I’m not weighing in on federal issues.’ But Senator McCain was a senator. He had to vote. He had to decide, `Am I in favor of pursuing these tax cuts or not?’ and he voted against the tax cuts – twice. That’s a very different position.”

If he actually believed in supply-side economics, he would have defended Bush’s tax cuts in 2003 and his reply to the question makes it obvious that he doesn’t get it now.
I wonder if National Review realized this before they endorsed him. Why would a conservative magazine endorse a candidate who doesn’t believe in supply-side economics?