While McCain and Romney tangled repeatedly - and at times caustically - during their nomination battle, Romney's move gives even more impetus to McCain's call for Republican party unity.

It also increases the pressure on Mike Huckabee to end his campaign, especially with the news that Huckabee is going out of the country this weekend to give a previously scheduled speech in the Cayman Islands.

McCain was already campaigning in New England when the Romney endorsement story broke, so he only had to go from next door in Rhode Island to Boston to get the former Massachusetts Governor's public backing.

McCain will be able to use this endorsement, along with others from people like Gary Bauer, to make the case to conservatives that he understands their concerns, but that it is time for All Good Republicans to get on the bandwagon, especially when you look at how motivated the Democrats have been during the primaries.

Also, with Barack Obama and Hillary Clinton still battling it out, the chances for fissures on the Democratic side could certainly outweigh those on the GOP end.

Is this the greatest thing to happen to McCain this year? Probably not. But it's still an important piece of the Election Puzzle for him. Better to have Romney (and many of his delegates too) than have Romney quietly showing his support for a Conservative Insurrection Against McCain.