Why is Mitt Romney endorsing John McCain?

Let me say that I have been a big supporter of Mitt Romney for years.  He's one of the best things going for conservative Republicans in a time when we desperately need something or someone to pull us through this Bush-led coup d'etat of the GOP.  Bush and his socialist wing of the party are slowly destroying any principles that the GOP has ever stood for.  McCain has more than aided the destruction - he's transparently befriended the mortal enemies of the party.

So while Romney has become more conservative with each passing year and is actively courting a slowly diminishing conservative bloc, why is he bothering to endorse a man with whom he has such obvious differences with?  I think a deal was made, and I have a theory as to what it might be.

Think back to Super Tuesday.  McCain swept the field and emerged as the clear front-runner.  Long-time GOPers and the entire Huckabee campaign staff were asking Romney to step aside for various reasons, but they were all pointing toward consolidated support for McCain.  But Romney refused and said he would remain in the race.  Only two days later, with the GOP delegate count remaining the same, Romney did a 180 and announced he was suspending his campaign.  Why the change of heart?

My best guess is that McCain and Romney made a deal.  McCain will be 72 years old next January when the next President takes office.  If McCain becomes our next president, after 4 years of failing health, anger management problems, and an awkward public personality, McCain will be a terrible candidate to run for re-election in 2012.  I think McCain and Romney made a deal that includes:

1. Romney must suspend his 2008 campaign for President
2. Romney will endorse McCain publicly
3. In 2012, McCain would not seek re-election
4. Romney will seek the 2012 GOP nomination with a crucial endorsement from President John McCain

Others are speculating that Romney may end up on the McCain ticket, but I doubt it.  McCain desperately needs to court Conservatives and the South, both of which Romney has not been a clear favorite.  More obvious VP candidates include Mike Huckabee, SC Senator Lindsey Graham, and Florida Governor Charlie Crist.  McCain's already received Graham and Crist endorsements, but I strongly believe that Lindsey Graham (an Air Force Colonel and Judge Advocate and an actual Iraq War Vet) has already made a deal with McCain to receive an appointment as U.S. Attorney General.  If Huckabee can work out a deal with McCain to leave the race, he will clearly be the favorite for VP.