Mr. Agnos's opponents hope to convert that frustration into votes, tapping the nostalgia of residents who widely believe that San Francisco used to be a paradise but is not anymore.

Ms. Alioto has used this tack most effectively. A member of one of the city's dynastic families, she declared her candidacy with her father, Joseph C. Alioto, by her side within sight of the historic North Beach church where she was baptized.

"The greatness of this city is its joie de vivre," said Ms. Alioto. "People have never been down and out like they are today. You can feel the lack of morale in the streets."

Ms. Alioto's entry into the race earlier this month scrambled the early betting line. Conventional wisdom had it that Mr. Agnos would struggle in the general election, face Mr. Jordan in a runoff and breeze to a second term, because San Franciscans are at heart a progressive lot and the former police chief is pitching tough policy on the homeless. The More Serious Threat

Now, Ms. Alioto is seen as the more serious threat, particularly in a runoff of likeminded liberals. A private poll, which prodded her entry into the race, shows her finishing a close second to Mr. Agnos in a general election.

The recurring subject on the campaign trail has been homelessness. At debates, where everyone has two minutes to speak, Mr. Agnos insists that his multiservice centers are an effective solution and that the homeless problem is not as bad as critics claim.

Jerry Roberts, the political editor for The San Francisco Chronicle, summarized the downfall of this approach. "By trumpeting his performance on the homeless issue as a model for the nation, Agnos is effectively asking voters to disbelieve what their own senses tell them is true," Mr. Roberts said.