With Mitt Romney dropping out of the race today, it is obvious to everyone that John McCain will be the Republican nominee. His VP pick is very, very important.
1. Due to his age, he needs to pick someone young enough to handle the rigors of office (in effect, McCain's VP is going to be the ceremonial head of state in many ways, the one doing all the traveling and visiting)
2. Because of his age, McCain also needs someone who can credibly step into the office on no notice.
3. McCain needs to make various different conservative constituencies happy
4. McCain needs someone who has not spent too much time in Washington
This rules out Mike Huckabee, who only makes certain social conservatives happy and has no foreign policy experience. It also rules out people like Colin Powell and Joe Lieberman, who appeal to the same voter demographic as McCain.
Based on these criteria, I think that South Carolina governor Mark Sanford should be top of his list. Why? Going back to my criteria
1. Sanford is 47 and charismatic
2. He can point to his time in the House and as governor to show he has experience and can run a government.
3. South Carolina has a lot of social conservatives, but Sanford has also made a name for himself as a pro-business fiscal conservative.
4. He only spent 6 years in Washington. He also has excellent private sector experience.
At the McCain rally last week I attended last week, I do not think McCain mentioned Sanford by name, but he did note that South Carolina has an energetic economy, thanks to good government that lets the private sector take off. (He was making a comparison with Michigan, and its poor business environment.)
I would also include governors Crist and Pawlenty, especially as Florida is a key state and Minnesota is possibly a swing state (though Pawlenty was twice only narrowly elected).
I also would consider Alaska governor Sarah Palin but she is a first term governor of a remote state.
So Sanford should be the first choice