LOS ANGELES » From the 73-story skyscraper that just broke ground downtown (the tallest in the West), to the blizzard of office, shopping and apartment complexes rising from there to the Pacific, construction is bustling in Los Angeles. Home prices are up, and the foreclosure rate is declining. Crime is down. There is a new mayor in City Hall. In many ways, Los Angeles, like many once-beleaguered cities across the nation, seems on the upswing.

Yet at this presumed moment of promise and potential, Los Angeles is enduring a series of blows that have challenged its self-esteem and even its long-term stability. Some appear more symbolic, like the departure of "The Tonight Show" for New York, followed by the plaintive appeal by Mayor Eric A. Garcetti that CBS move "The Late Show" to Los Angeles when David Letterman retires next year. Others are beyond its control, such as the disconcerting wave of earthquakes that have rumbled the region in recent weeks, reminding residents of how unprepared Southern California is for a cataclysmic temblor.

But the most worrisome blow by far is a scathing verdict on Los Angeles’ civic health that was delivered in a one-two punch — the second on Wednesday — by a committee of lawyers, developers, labor leaders and former elected officials who make up something of the Old Guard here. The Los Angeles 2020 Commission presented a catalog of failings that it said were a unique burden to the city: widespread poverty and job stagnation, huge municipal pension obligations, a struggling port and tourism industry and paralyzing traffic that would not be eased even with a continuing multibillion-dollar mass transit initiative.

"Los Angeles is barely treading water, while the rest of the world is moving forward," the commission said. "We risk falling further behind in adapting to the realities of the 21st century and becoming a city in decline."

"Year by year, our city — which once was a beacon of innovation and opportunity to the world — is becoming less livable," the report said.

The first part of the report was released in December. Its bleak portrait of Los Angeles’ future was designed to break through and draw attention to the city’s plight like "an alarm clock," said Mickey Kantor, a former U.S. secretary of commerce who is the co-chairman of the commission.

But as exhaustive as Chapter 1 was in laying out problems, the follow-up presented here Wednesday was strikingly less ambitious and specific, testimony to what municipal leaders have long said was the intractability of the challenges, the difficulty in getting things done in a community with a history of lackluster civic involvement and an institutionally weak mayor.

© 2014 The New York Times Company