Joe Biden will help Barack Obama fight John McCain on the campaign trail and reassure voters worried about Obama’s experience, former Denver mayor and Clinton cabinet official Federico Pena told PolitickerCO.com Sunday afternoon.

“Around the country, for the few people who are still undecided, one of the reasons they’re undecided is because they have questions about Barack’s youth, his so-called ‘inexperience,’” said Pena, an Obama national campaign co-chair, at the City to City Panchanga block party in Denver. “Having someone like Joe Biden, with his grey hairs – literally and figuratively – answers the question of experience for those who are concerned about experience.”

Pena described Biden as “a fighter” who will take on McCain -- especially about foreign policy issues.

“He’s going to take on the Republican ticket frontally, and he knows John McCain very well, and there’s not going to be very much that John McCain can say during this campaign that Joe Biden doesn’t know,” Pena said.

Pena said he expects Obama and Biden will visit Colorado frequently through the November elections and said the Obama campaign will continue to expand in the battleground state.

“We’ve got nine (field) offices set up (in Colorado) already. We’re probably going to have 16 offices before we’re through,” Pena said.