In the aftermath of the defeat of Mayor Giuliani’s bid for the presidency, Mr. Giuliani will no doubt want to take a vacation and, after that, return to his lucrative law and consulting practices. But as the postmortems are being written on the Giuliani campaign, we wouldn’t discount the possibility of a future career in public service. If Senator McCain wins the presidency, Mr. Giuliani would be a fine choice as secretary of homeland security or as ambassador to, say, Saudi Arabia or to the Iranian democratic opposition.

If Senator Clinton were to gain the presidency, it would create an opening for the job of senator from New York. Governor Spitzer would almost certainly appoint a Democrat to the job on an interim basis, but that Democrat would be open to a Republican challenge in the next election. And while Mr. Giuliani has an executive rather than legislative personality, we have no doubt that he could get a lot done as a senator and do a fine job representing the state of New York.

Mr. Spitzer’s own job, as governor, is another one where Mr. Giuliani could have an enormous impact. And there is the mayoralty, where Mr. Giuliani had his finest — and most difficult — hours. Term limits prevent a mayor from serving two consecutive terms, but would allow Mr. Giuliani to seek a return to the office in which he did so much to improve this city. It might seem far short of the White House dreams, but Gracie Mansion is newly renovated. If Mayor Bloomberg runs successfully for the White House, the mayor’s office may be open for occupancy sooner than anyone expects.