"Everybody is out there trying to get part-time jobs, putting even more stress on their families," he said.

The Pew study is based on an analysis of Census Bureau and Federal Reserve Board data, as well as a telephone survey of 2,508 adults from July 16-26, 1,287 of whom identified themselves as middle class. The poll has an overall margin of error of plus or minus 2.8 percentage points, and 3.9 percentage points for the middle-class segment.

Blaming Lawmakers

Most who consider themselves middle class say it's a struggle to maintain their standard of living. Eighty-five percent say it's harder to do than it was a decade earlier, according to Pew. Tight finances led 62 percent to reduce spending in the past year, compared with 53 percent who said so in 2008, soon after the onset of the recession.

Rich Morin, a senior Pew editor, said in the conference call that widespread dissatisfaction with Congress may become evident in November. Ninety-one percent of middle class respondents in the Pew survey pinned "a lot" or "a little" blame for the poor economy on lawmakers.

"Everybody's ready to point the finger at Congress," he said. "And if you restrict the respondents to registered voters, fingers blame Congress even more. So this is not particularly good news for incumbent members of Congress."

Tempered Optimism

The rout has tempered middle-income Americans' optimism. When asked about their children's future, 43 percent said they would have a higher standard of living than their own, while 26 percent said it would be worse. That's less sanguine than four years earlier, when 51 percent said the kids would be better off, and 19 percent said they wouldn't.

In Lower Makefield Township, Pennsylvania, Frank Arcoleo, 59, who has relied on his wife's income since his consulting business slowed, said he's afraid his two teenagers won't be able to match his standard of living when they're older.

"I just don't know what life is going to be like for my son," Arcoleo said. "He's having to be much more practical about his education than I ever had to be, because being well- educated isn't enough. You have to have specific skills these days."