A Pentagon focus
Some observers said they could possibly see McCain keeping on Defense Secretary Robert Gates, who has been in the job for only a little more than a year. McCain and Gates generally are in alignment on the Iraq war, a major emphasis of McCain's. But McCain, a former Navy pilot with years of national security experience, is expected to exude heavy influence on the Pentagon regardless of who holds the post.
"Like (former President Dwight) Eisenhower, McCain would probably be his own secretary of defense," said John J. "Jack" Pitney Jr., who teaches politics and government at Claremont McKenna College in California.
McCain also has vowed to immediately shutter the Guantanamo Bay detention camp and has clashed with the Bush White House over the treatment of suspected terrorists. That means any Justice Department and Defense Department officials who justified the use of what McCain considers torture are sure to be dispatched in his administration.
"I wouldn't see a big shakeup at the Pentagon, but I would expect that most of the political appointees would be gone as a matter of course, but especially if they'd been involved in the decisions about torture," said James Pfiffner, a presidency scholar and professor of public policy at George Mason University in northern Virginia.
Bush staffers would leave
In general, few observers expect McCain to keep many, if any, Bush administration figures. Even if Bush didn't continue to poll poorly, new presidents traditionally clean house.
"He's going to want his own people in there," Pitney said of McCain. "During the campaign, he'll probably want to emphasize that his administration would be a new beginning. I think he realizes that a lot of Bush holdovers would get him off to a bad start in public opinion."
Sen. Jon Kyl, R-Ariz., a McCain supporter, predicted wholesale turnover regardless of McCain's feelings about the current Cabinet.
"Very few people in a political position expect to stay into the next administration — virtually none," Kyl said. "If John McCain comes in and says, 'Gee, I'd like to have you stay,' maybe somebody would be willing to stay, but the expectation is that the job ends at the end of this year."