In the end, the theory of the indispensable man failed. Mr. Giuliani left office on schedule at the end of 2001. Both the city and the republic survived.

Now Mr. Bloomberg is making noises that sound suspiciously like an echo of that theory. After years of speaking unswervingly in favor of term limits, he has wavered. He now seems open at least to the concept of a voter-dodging maneuver by the City Council to give him and other city officials a third term beyond 2009.

How serious he is about this is hard to tell. Mr. Bloomberg has minions of his own. They have floated more trial balloons than the Macy’s parade in various attempts to stave off lame-duckdom. This third-term business may be just another way to keep his name front and center as his days at City Hall wind down.

But it just could be that Mr. Bloomberg, like Mr. Giuliani, has never fully absorbed Charles de Gaulle’s admonition about indispensable men. The graveyards, de Gaulle said, are full of them.

Not bad advice for would-be presidents, too, come to think of it.