Republican Sen. John McCain (search) has personally rejected John Kerry's (search) overtures to join the Democratic presidential ticket and forge a bipartisan alliance against President Bush, The Associated Press has learned.

Kerry has asked McCain as recently as late last month to consider becoming his running mate, but the Arizona senator said he's not interested, said a Democratic official who spoke on condition of anonymity because Kerry has insisted that his deliberations be kept private. A second official familiar with the conversations confirmed the account, and said the Arizona senator made it clear he won't change his mind.

Both officials said Kerry stopped short of offering McCain the job, sparing himself an outright rejection that would make his eventual running mate look like a second choice.

"Senator McCain categorically states that he has not been offered the vice presidency by any one," said McCain's chief of staff, Mark Salter, who would not confirm the officials' account.

Kerry spokeswoman Stephanie Cutter declined to comment.

The development may lay to rest speculation that Kerry and McCain would reach across Washington's deep partisan divide and forge an unprecedented political partnership.

The notion has been rife with obstacles from the start -- McCain is a strong-willed conservative and Kerry a liberal from Massachusetts who would be loath to surrender presidential responsibilities that McCain might demand.

But the fellow senators and Vietnam veterans (search) are friends, their bond sealed as they worked together to help President Clinton normalize relations with Vietnam. Clinton, who avoided service in the war, needed the political cover from Kerry, a decorated Navy veteran, and McCain, a prisoner of war.

McCain's cool relationship with Bush fostered Democrats' hopes, but the senator has repeatedly declared his allegiance to the GOP. McCain lost a bitter campaign against Bush for the 2000 Republican nomination, leaving wounds that may never heal.

McCain has said publicly he had no intention of serving as vice president, but he left the door open just enough to create a constant buzz. His advisers say McCain has ruled out serving under Kerry, despite his respect for the Democrat.

Officials close to Kerry have reached out to McCain's advisers in hopes of persuading the senator to join the ticket.

A GOP maverick, McCain jumped to Kerry's defense when the White House accused the Democrat of being weak on defense. "This kind of rhetoric, I think, is not helpful," he said in March, admonishing the White House.

A shoot-from-the-hip style has made McCain one of the nation's most popular politicians, a champion of campaign finance reform and critic of pork-barrel spending -- two issues that antagonized his fellow lawmakers. They accuse him of being a showboat, but a politically potent one.

A recent CBS News poll showed that a hypothetical Kerry-McCain ticket had a 14-point advantage over Bush-Cheney among registered voters, 53 percent to 39 percent. That's a huge improvement over polls showing Kerry tied or slightly ahead of Bush in head-to-head matchups.

Kerry is giving serious consideration to Sen. John Edwards (search) of North Carolina, Rep. Dick Gephardt (search) of Missouri and retired Army Gen. Wesley Clark (search) of Arkansas -- all former primary rivals -- as well as Iowa Gov. Tom Vilsack (search).

When Vice President Dick Cheney's political status was shaky, McCain's name emerged as a potential replacement and officials close to the senator never ruled out that possibility. Bush has since said Cheney will remain on the ticket.

A new Associated Press poll conducted by Ipsos-Public Research shows that 51 percent of registered voters believe Bush should keep Cheney on his ticket, with 43 percent wanting him to pick somebody else.

Among those also mentioned as potential Kerry running mates are Sens. Bob Graham (search) of Florida and Evan Bayh (search) of Indiana; former Sen. Bob Kerrey (search) of Nebraska; and Govs. Janet Napolitano (search) of Arizona, Mark Warner of Virginia, Bill Richardson (search) of New Mexico and Ed Rendell (search) of Pennsylvania.

McCain, a Navy bomber pilot, spent more than five years as a prisoner of war in Vietnam. Kerry, who also served in the Navy during Vietnam, came home with three Purple Hearts and Bronze and Silver Stars and became a leader of Vietnam Veterans Against the War. At one protest in 1971, he threw away war medals belonging to other veterans and cast his own military ribbons over a fence. McCain heard about it while he was still being held captive in the Hanoi Hilton.

After McCain was elected to the U.S. House, he campaigned against Kerry in his first Senate race, faulting him for tossing away those medals and ribbons. But the two came to terms in the Senate and began working together.