On Tuesday, Lt. Gov. David A. Paterson waited. Around noon, he was driven from his home outside Albany to the Capitol, raising expectations that Gov. Eliot Spitzer would soon resign and that Mr. Paterson was about to become the state’s 55th governor  and the first African-American to hold the post.

Neither happened. Mr. Paterson returned home and waited some more.

With Mr. Spitzer’s political future in grave doubt, Mr. Paterson, 53, a Brooklyn-born and Harlem-bred politician, has become Albany’s man of the moment. Widely considered smart, amiable and disarmingly candid, he is also largely untested.

In 2006, Mr. Paterson surprised the Democratic establishment by giving up the possibility of becoming majority leader if the Democrats captured the State Senate  one of Albany’s muscular three men in the room  to run for lieutenant governor, a largely ceremonial post.

But this week, Mr. Paterson’s political gamble suddenly appeared to be on the brink of paying off, if in an unexpected and unintended way. If Mr. Spitzer resigns, Mr. Paterson would become only the third black governor of any state since Reconstruction.