Both Romney and McCain have plenty of money and Romney donated to a NRO organization during the '08 campaign...follow the money.
It's worse than that greyfoxx39. Remember: National Review had a big internal debate over whom to endorse of their top two choices, Mitt Romney or RUDY GIULIANI. Ramesh Ponnuru was really the only main guy/girl looking at anyone else, and he was backing McCain from the start.
Since that debate, they have been 1,000,000,000% pro-Romney, and have basically endorsed him for 2012 three years ahead of the primaries.
I am not surprised at the McCain endorsement, not at all.