Before Jack Bauer saved the United States from a potentially devastating nuclear missile strike, John McCain saved the U.S. Senate from an equally dangerous self-inflicted nuclear attack.

To be sure, it was just a coincidence that the intrepid hero of Fox television’s “24” saved Los Angeles from a terrorist-launched missile on the night the Arizona Republican helped broker an agreement on judicial nominations that prevented the Senate from a devastating implosion.

But the similarity between television’s often too-good-to-be-true counterterrorism agent and the heroic former Vietnam War prisoner turned bipartisan broker helps explain the appeal that has vaulted Mr. McCain to the top of the early 2008 Republican polls.

Both the frenetic Mr. Bauer and the senator whose life is the stuff of legends – a film based on his life will be shown on television this weekend – are strong-willed leaders whose successes defy reality while they make waves with establishment skeptics.

Throughout three seasons, Mr. Bauer has never hesitated to push the boundaries of acceptable behavior and defy superiors to achieve desirable ends.

Similarly, Mr. McCain has been a maverick throughout his career – as a rules-defying midshipman at the U.S. Naval Academy, a prisoner of the North Vietnamese and a politician at odds with his party’s conservative orthodoxy.

In his initial years in Congress, Mr. McCain stood out mainly for his heroic past. In 2000, his maverick streak emerged nationally with a dramatic but ultimately unsuccessful presidential bid. Bypassing the Iowa caucuses, he ran an imaginative and successful New Hampshire primary campaign marked by unusual openness to the press and public.

Later, after being done in during the South Carolina primary by a fierce Karl Rove-engineered assault on behalf of George W. Bush and twisted ads of dubious parentage, he mounted a dramatic, though possibly self-defeating, attack on the GOP’s leading religious conservatives.

Since 2000, Mr. McCain has often been an unpredictable voice in the tradition-bound, hierarchical GOP. He opposed Mr. Bush’s 2001 tax cuts as too big and formed alliances with Democrats, including one with Sen. Russ Feingold that passed a campaign-reform bill that GOP leaders hated.

In 2004, however, he displayed his innate pragmatism by downplaying substantive and personal differences with Mr. Bush in the interests of a GOP victory and his own future prospects.

But the senator’s role in crafting the Senate agreement showed he has abandoned neither his maverick course nor his willingness to reach beyond the GOP for a greater good.

Though Mr. McCain was far from the only key figure in achieving the breakthrough that prevented the showdown, his role provided a dramatic contrast with that of a potential 2008 rival, Majority Leader Bill Frist.

Mr. McCain, backed by moderates of both parties, succeeded, at least for now, in re-establishing the bipartisan center as the decisive bloc in a sharply divided Senate.

Mr. Frist, who initially gained his leadership post with a boost from the Bush White House, failed in a bid to force the Senate into an all-or-nothing showdown that would have undone its 200-year-old tradition of unlimited debate and made it a more loyal GOP adjunct like the House.

Mr. Frist’s disappointment was evident in the tone and language of his post-agreement remarks and was echoed by conservative groups who fueled this fight and indicated in advance they would not forget the roles of its leading players.

They stand as a formidable barrier to Mr. McCain’s ill-concealed intentions of mounting a 2008 bid for the presidency – this time as the closest thing to a natural GOP heir in a party that has generally preferred political primogeniture.

He faces other difficulties, too: He will be 72 before the next election. He sometimes has difficulty concealing a fierce temper. And the GOP is, if anything, more dominated by its conservative majority than in 2000.

On the other hand, like Jack Bauer, he can get things done – no small feat in today’s polarized climate. That ability should count for a lot, whether in politics or in fictional counterterrorism.

Carl P. Leubsdorf is Washington bureau chief of the Dallas Morning News.