Among these people, who tend to reside in the middle of the ideological spectrum, the president’s job-approval rating fell to 45% from 60% in April…

In particular, the survey suggests, independents are developing gnawing fears about government spending. They are markedly more worried about the federal budget deficit as an economic issue than are Americans in general, and they are more likely to be skeptical of Mr. Obama’s plan for a health-care overhaul.

Above all, though, independents are starting to simply view the president as more liberal than they expected. The share of independents who say Mr. Obama is a liberal has risen to a substantial 64% from 46% two months ago. A large portion of them actually classify him as “very liberal.” That’s a particular problem because independents tend to view themselves as center-right — 78% call themselves moderate or conservative — so they see a president moving to the left of where they are.