Mitt Romney's endorsement of John McCain was very satisfying, if only because it sticks it to Mike Huckabee.
The fact remains that Romney's going to need more allies than he had in 2008. Endorsing McCain is one step in that direction. Now, he will have the support of a number of the Republican establishment. Regan was willing to show unity with Ford after 1976.
If Romney is to win in 2012, he also needs to make it very clear that he will not be pushed around, and that he will be able to stick it to folks who diss him. This he has done, and Huckabee knows it, which must be why he has to be the first high-profile case of Romney Derangement Syndrome.
All in all, the GOP will be Romney's after November 2008, no matter what. He's shown he is a team player, but he also is the best we're likely to get in 2012.