McCain, Obama VP Talk Heats Up

Crist's name also has come up. He endorsed McCain before the Florida primary that put McCain on track to win the nomination. On paper, Florida remains a swing state. But older demographics and an increasingly Republican-leaning electorate already favor McCain. Crist adds little to the ticket at this point.

Political bettors at intrade.com concur. They have Romney leading the field with a 33% chance of becoming the nominee. Pawlenty sits in second place with close to a 20% chance, while nobody else in the field rises above 10%.

Obama's Contenders

Obama's overseas trip has overshadowed speculation about whom he'll tap as a running mate. Several prominent choices from key Southern states have removed their names from contention including former Sen. John Edwards of North Carolina and Sen. Jim Webb from Virginia.

Obama's strategy in selecting a candidate comes down to two options. First, he could choose primary rival Sen. Hillary Clinton (D., N.Y.) in an effort to unite the Democratic Party, while also potentially attracting more female and senior voters. Both voting blocs strongly supported Clinton.

Despite media reports that Clinton has no interest in the job, she's still in the running. She has not publicly removed her name, which signifies she's interested in the position. I think she would take the position if it were offered.

It's also clear that she has been vetted by his vice presidential selection team. Moreover, she has continued to work on behalf of Obama and urged her fundraisers to donate to his campaign.