NEW ORLEANS  There is disappointment but little surprise here at a federal judge’s grudgingly absolving the Army Corps of Engineers of liability in the flooding of New Orleans after Hurricane Katrina.

Although the decision, issued Wednesday, was sharply critical of the corps, the judge’s finding has if anything only hardened the ill feelings against the government that have hung over this city since the storm.

The plaintiffs in the class-action suit dismissed by the judge were many of the hundreds of thousands of people who filed claims here against the corps last year because of the levee breaches that flooded the city. They lined up in cars and on foot and jammed the streets around the agency’s district headquarters, acting out what has been a loudly spoken article of faith since the days in 2005 when water covered 80 percent of New Orleans and ruined the homes of thousands: the corps  not nature, not a record-breaking storm surge and not local politics or local negligence  was to blame.

The judge, Stanwood R. Duval Jr. of the Federal District Court here, a son of South Louisiana, heartily seconded that notion on Wednesday, suggesting that the corps was guilty of “gross incompetence.” But Judge Duval said he was powerless to rule favorably on the lawsuit because the Flood Control Act of 1928 granted legal immunity to the government in the event of failure of flood control projects like levees.