Antonio Villaraigosa (l) and Los Angeles Mayor James Hahn lead the 'March of Gratitude' organized by the Museum of Tolerance
On May 17, Los Angeles will select a mayor, and the city's shifting demographics are helping Hispanic contender Antonio Villaraigosa. He is the former speaker of the California assembly, and is now a member of the Los Angeles city council. For incumbent mayor James Hahn and for his challenger, winning requires building coalitions.

Former Los Angeles mayor Sam Yorty, who served three terms in the post, reportedly said that anyone who wanted the job after reading the city charter would have to be out of his mind. Los Angeles city government was given its current form a century ago by reformers who feared corruption, and hoped to avoid it by decentralizing power. So the Los Angeles mayor has been a figurehead with limited authority, and none at all over issues like education.

But that topic ranks high among voter concerns, and has become an issue in this election. Here is Mr. Villaraigosa speaking at a recent rally.

"We need leadership that is going to demand that our schools keep out kids safe in our schools," said Antonio Villaraigosa.

Mr. Hahn has also promised safe and effective schools. He has gone even further, urging that the mayor be granted the power to appoint three members of the school board, in addition to the seven members who are now elected.

Los Angeles has nearly four million people. Hundreds or even thousands may attend campaign events, but millions hear the message of the candidates on television. In political ads, both contenders have questioned the fundraising practices of their opponent. First, here is a segment of an ad from the Hahn campaign, which begins with a comment by Mr. Villaraigosa.

Villaraigosa: "I will lead by example."

Narrator: "The Villaraigosa example of special favors for special contributors. Los Angeles just cannot trust Antonio Villaraigosa."

The Villaraigosa campaign points a finger at the mayor in this ad:

"They say 'follow the money,' and almost all the corruption is tied to fundraising for Hahn's campaigns. Isn't it time for a change?"

There are also more focused messages aimed at specific communities, from Asians in Chinatown to Jewish voters on the city's west side. Mr. Villaraigosa has overwhelming support among Hispanic voters, who form 20 percent of the electorate. But the race for mayor is always about building coalitions, says analyst Sherry Bebitch Jeffe of the University of Southern California. She says in the last election, Mr. Hahn forged an unusual partnership with inner-city blacks and whites in the San Fernando Valley section of Los Angeles.

"And one of the reasons Hahn is in trouble is that he could not hold that coalition together," said Sherry Bebitch Jeffe.

Many African Americans feel affection for the mayor, although he is white. His father was a popular politician who for many years represented the largely black neighborhood of South-Central Los Angeles.

But others are angry with the mayor for working to remove the city's former police chief, Bernard Parks, who is black. Mr. Hahn said a change was needed in the scandal-ridden department. Mr. Parks now serves on the city council, and has criticized the mayor and endorsed fellow council member Antonio Villaraigosa.

Mr. Villaraigosa has received other important endorsements among black community leaders, who supported Mayor Hahn in the last election. Danny Bakewell, an African-American activist and newspaper publisher, endorsed the challenger, introducing him at a recent rally.

"Join me please in welcoming the next mayor of the city of Los Angeles, Antonio Villaraigosa," said Danny Bakewell.

Last month, Mayor Hahn was trailing in the polls by 18 percent. He has narrowed the gap, but still trails by 11 percent. If Mr. Villaraigosa wins, he will be the first Hispanic mayor in Los Angeles in more than 130 years.

But he would face the same problems as his predecessors: a rapidly growing city with a governing structure put in place 100 years ago, and an increasingly diverse population.

Ms. Jeffe says the next mayor, whoever it may be, must use his bully pulpit, and communicate directly with the voters to urge changes. He can also influence the city through political appointments to agencies and commissions. She says the most effective mayors have done this in the past, shaping policy despite the limitations of their position.