There’s this theory going around that President Bush will govern in his second term as a lame duck, with nothing more to gain or lose politically. But that isn’t how Bush is thinking about it. He has Jeb to consider.

Even before this year’s election, Jeb Bush was being asked about his aspirations. On Oct. 17, he declared on ABC, “I’m not going to run in 2008. That’s not my interest.”

But last week, in a meeting with the Washington Times editorial board, Ken Mehlman, the new chairman of the Republican National Committee, put Jeb back in the race.

Responding to a question, Mehlman mentioned eight potential candidates for 2008: Senate Majority Leader Bill Frist, Virginia Sen. George Allen, Colorado Gov. Bill Owens, Arizona Sen. John McCain, Massachusetts Gov. Mitt Romney, George Pataki, Rudy Giuliani – and Jeb Bush.

RNC spokesman Brian Jones insists Mehlman was just speculating about politicians who are being discussed in the media. But Mehlman is not a neutral commentator. He works for George Bush. If the president’s brother were really out of the running, the RNC chairman would not mention him.

In fact, the Bushes have been thinking about Jeb’s candidacy for years.

One of the main reasons Dick Cheney got a second term was to make sure there would not be an incumbent vice president with presidential ambitions in 2008.

Four years is a long way off. But if Jeb does run, he has a real shot at the nomination. Pataki and Giuliani may be too liberal on “values” issues to win red-state primaries. Romney’s from Massachusetts. Owens and Allen are unknowns. McCain, the media’s candidate, is a cancer survivor who will be 72 in 2008. Frist has a golden resume, but he’s a snooze.

Jeb is head and shoulders above this field. He’s the popular governor of a crucial state. Fluent in Spanish, married to a Mexican, the darling of the Cuban community, he has vast appeal to the constituency the GOP most covets: Hispanics. He’s conservative on social issues but comes across as less regional and ideological than his brother George. Jeb is a southern Republican who sounds like a Democrat. In 2002, he won re-election in Florida, an evenly split state, by 13 points.

If Jeb’s last name weren’t Bush, he would be the obvious early favorite for 2008. But it is, and some experts believe it disqualifies him. Supposedly, the public will not elect two brothers in a row. After all, it has never happened.

But modern American politics is strewn with the debris of such precedents. Before the Clintons, nobody dreamed that a former first lady could become a senator and viable presidential contender. Until Ronald Reagan, the idea of a Hollywood actor in the White House seemed absurd. In 1960, John Kennedy appointed his 35-year-old brother, Bobby, attorney general, and two years later, he leaned on Massachusetts Democrats to make the spectacularly unqualified 30-year-old Teddy a senator.

What Reagan, Kennedy and the Clintons shared was boldness and an understanding of how fragile the “rules” really are. By the time Jeb wins the nomination in the primaries – and its hard to see him losing with the backing of the Bush machine – the public will have gotten used to the idea.

Can Jeb be elected president? That largely depends on his big brother. If, in 2008, the president is seen as successful and popular, a lot of Republicans will want a Bush third term (just as many Democrats dreamed of another four years for Bill Clinton). The Constitution makes Dubya ineligible for a three-peat but it does not rule out a third consecutive Bush administration. That’s why it would be a mistake to view the next four years as a terminal presidency.