The Boston Herald reported Friday that if Romney wants to be McCain's running mate then he should offer to help bankroll the general election campaign.

"Romney has to pull out a checkbook," Republican analyst Jim Nuzzo said, "and say, 'John, how large a check should I write?'"

Romney, who was a venture capitalist, also "has to demonstrate he has the ability to galvanize support throughout bedrock Republicans," Nuzzo added.

Among other potential vice presidential candidates who were invited to McCain's ranch in Sedona, Ariz., for Memorial Day weekend are Florida Gov. Charlie Crist, Louisiana Gov. Bobby Jindal and Kansas Sen. Sam Brownback.

Those close to Romney say he is not angling for vice president.

"He's not focused on vice president, he's focused on helping to elect John McCain," said Eric Fehrnstrom, who served as Romney's spokesman during the former governor's unsuccessful campaign for the Republican presidential nomination.