As Mitt Romney moves closer and closer to clinching the GOP presidential nomination, speculation about his vice presidential pick will start to increase.

This week the Washington Post argued that the choice would focus on ideology:

“Historically, and presently, the central fault line inside the GOP has been between the moderate/establishment wing and the movement conservative wing,” explains GOP consultant Jon Lerner. “The choice of running mate has very frequently been used to unite the two wings.”

This trend played out in 2008 when McCain chose conservative Sarah Palin over his preferred choice of Joe Lieberman, an independent. And in 2000 "compassionate" conservative George W. Bush picked the more traditional conservative Dick Cheney as his running mate.

Yet today Talking Points Memo reports that the moderate Romney has also had trouble appealing to independents, and may need a VP to help him bridge that gap:

When Romney’s unfavorable numbers first started to jump up in February, Obama began to take a much larger share of unaffiliated voters.

Appealing to the right or moving to the center? What's Romney's smarter VP move? Vote now on Facebook!