RALEIGH, N.C. — North Carolina Sen. Richard Burr said Monday that he would accept a spot on John McCain's presidential ticket if asked by the Arizona senator.

Burr has joined McCain on the campaign trail several times over the past year, stumping for him in places like Iowa, New Hampshire and South Carolina. He and his wife were with McCain on Super Tuesday, and the two senators often discuss strategy and policy together.

Political insiders said Burr is a rising star in the Republican Party whose conservative track record would balance a more moderate McCain. Burr also could boost McCain's fortunes in the South, obervers said.

Burr said McCain is focused on winning the nomination and that the two haven't discussed teaming up for the November election. But the first-term senator said he would agree to run as a vice president if McCain asked him.

"I think anyone who would say they wouldn't (run) would be disingenuous," he said. "If the commander-in-chief calls upon you, it's our responsibility as Americans to say, 'Yes sir' or 'Yes ma'am.'"

Still, Burr said he doubts that McCain has started whittling down a list of potential running mates.

"I don't think there's a list. Any nominee would want to wait to see who they are running against before they go through that process," he said.

Though the two senators disagree on some policy issues, such as campaign finance reform and some aspects of illegal immigration, Burr said McCain is a true conservative with the experience to deal with the key issues facing the nation, such as the war in Iraq.

The Southerner said he's not planning on joining McCain on the ticket, adding that he doesn't expect McCain to choose a running mate until "much later in this calendar year."

"People mistake my intent, which is to get (McCain) elected, versus a belief that this is an audition," Burr said.

More than a year ago, McCain rattled off a list of four senators who would be vice presidential possibilities, including Burr, Lindsey Graham of South Carolina, John Thune of South Dakota and John Sununu of New Hampshire.

"He's mentioned my name and others, but the reality is that speculation and popularity contests are popular," Burr said.

Should the two join forces on a ticket, Burr would provide McCain some distinct accents. McCain, who has been in Congress for 26 years, would be the nation's oldest president on inauguration day at age 72; but Burr, a fresh face on Capitol Hill, is only 52. And the North Carolina senator provides some roots in the South for McCain, who has so far lost most primaries in the region to former Arkansas Gov. Mike Huckabee.

John Dinan, a political science professor at Wake Forest University, said Burr - a darling among conservatives - could help shore up McCain's support among the Republican base, something he may need to win nine months from now.

"In most primaries you shore up the base and then run to the middle," Dinan said. "But McCain got moderates and independents in the primary, and now he needs to shore up the base of the party."

He said Burr could bring some problems to the ticket. He isn't well known and doesn't have executive experience, and Dinan said there's always the chance that voters would dislike the idea of voting for two sitting senators.

Burr was elected to the Senate in 2004, after spending 10 years in the House of Representatives. He serves as the ranking member of the Senate Veterans Affairs Committee, and sits on several other committees including the Senate Intelligence Committee.

He will be up for re-election in 2010.

Republican gubernatorial candidate and state Sen. Fred Smith said Burr would "make an outstanding vice president."

"I think he'd carry his home state whereas John Edwards wasn't able to carry his," he said.

Edwards was also a first-term senator from North Carolina when he tried four years ago to make the leap to the executive branch as a candidate for president and then later a running mate with Massachusettes Sen. John Kerry. Edwards dropped a second presidential bid last month.

Burr already has some vice presidential blood. He's a distant cousin of Aaron Burr, who nearly became the nation's third president before taking the vice presidency behind Thomas Jefferson.

"I'm sure that as the year goes on, there may be some greater focus on that," Burr said with a laugh and wry smile.