Many Republicans hope his pick for vice president will give him a boost

NBC NATIONAL NEWS — Mitt Romney off the campaign trail Friday in Boston. He's working on choosing a running mate, with his campaign in a slump.

Three new polls show Romney trailing President Obama by seven points or more.

Is he off message?

Romney's put up an ad about welfare, and an ad about religion. He took an overseas trip that was marred by gaffes. Conservatives are demanding Romney prove he's focused on the economy. 

A big test is Romney's vice president choice. The Wall St. Journal is pushing controversial conservative Paul Ryan, and Romney echoed phrasing from their recent editorial when asked who he might choose.

"I don't think I have anything for you on the VP running mate. Other than I-- I certainly expect to have a person that has a strength of character, a vision for the country," he said.

Paul Ryan's vision is shrinking Medicare to cut the deficit. He's to the right of Romney, which if history is a guide, also makes him a likely Republican running mate.

"It's almost always an ideological matching, that is if you're perceived as a moderate, you pick the conservative," says the Washington Post's Chris Cillizza.

A decision is expected as early as next week.