David Zahniser, the City Hall bureau chief reporter for Copley News Service, writes in the Sunday Daily Breeze that insiders are "amazed" at Mayor Jim Hahn's political vulnerability.

Only a year ago it seemed like Los Angeles Mayor James Hahn was on a triumphant roll: He crushed a campaign to break up his city, won praise for his selection of a new police chief and drew cheers for his plan to hire hundreds of new officers.

Twelve months later, the picture is considerably more bleak.

With a federal corruption investigation focusing on his office and high-profile politicians lining up to unseat him, Hahn has become the city's most vulnerable incumbent mayor in a generation, political experts say.

"Not only in Los Angeles, but in the history of big-city mayors, it's rare to get this kind of a challenge," said Jaime Regalado, who heads the Edmund G. "Pat" Brown Institute at California State University, Los Angeles.

Hahn gave a 10-minute speech Saturday at the annual Mayor's Prayer Breakfast, also attended by one of his reelection rivals, councilman Bernard Parks. Hahn's other rivals continue to gear up. State Sen. Richard Alarcon introduced his girlfriend and daughter around at a book party for The Nation at Arianna Huffington's on Friday, attended by Jane Fonda, Larry David, authors, journalists and political types, among them the (outnumbered) former state Republican chair, Shawn Steel. Alarcon asked one highly placed Democrat there for support but apparently forgot that she had been a backer of Richard Katz, who Alarcon defeated in a bitter primary clash that left scars in the party over ethnicity issues. Meanwhile, Bob Hertzberg enthuses online on the response to his blog, but it looks as if he won't be posting daily. He's posted twice since launching on April 20, and has apparently learned one of the realities of political blogging. The top entry begins: "Please note: This blog is intended to be a discussion of issues facing Los Angeles. Personal attacks on ANY person are subject to removal."

* Monday add: The Times' Noam Levey weighs in with a mini-profile of Hahn, and Rick Orlov takes the mayor's political temperature in the Daily News. Also, the L.A. Business Journal Q-and-A's with Laura Chick.

Mayor Hahn's website
Senator Alarcon's website