Justice Department officials over the last six years illegally used “political or ideological” factors to hire new lawyers into an elite recruitment program, tapping law school graduates with conservative credentials over those with liberal-sounding resumes, a new report found Tuesday.

The blistering report, prepared by the Justice Department’s inspector general, is the first in what will be a series of investigations growing out of last year’s scandal over the firings of nine United States attorneys. It appeared to confirm for the first time in an official examination many of the allegations from critics who charged that the Justice Department had become overly politicized during the Bush administration.

“Many qualified candidates” were rejected for the department’s honors program because of what was perceived as a liberal bias, the report found. Those practices, the report concluded, “constituted misconduct and also violated the department’s policies and civil service law that prohibit discrimination in hiring based on political or ideological affiliations.”

The shift began in 2002, when advisers to then-Attorney General John Ashcroft restructured the honors program in response to what some officials saw as a liberal tilt in recruiting young lawyers from elite law schools like Harvard and Yale. While the recruitment was once controlled largely by career officials in each section who would review applications, political officials in the department began to assume more control, rejecting candidates with liberal or Democratic affiliations “at a significantly higher rate” than those with Republican or conservative credentials, the report said.

The shift appeared to accelerate in 2006, under then-Attorney General Alberto R. Gonzales, with two aides on the screening committee — Michael Elston and Esther Slater McDonald — singled out for particular criticism. The blocking of applicants with liberal credentials appeared to be a particular problem in the Justice Department’s civil rights division, which has seen an exodus of career employees in recent years as the department has pursued a more conservative agenda in deciding what types of cases to bring.

Applications that contained what were seen as “leftist commentary” or “buzz words” like environmental and social justice were often grounds for rejecting applicants, according to e-mails reviewed by the inspector general’s office. Membership in liberal organizations like the American Constitution Society, Greenpeace, or the Poverty and Race Research Action Council were also seen as negative marks.

Affiliation with the Federalist Society, a prominent conservative group, was viewed positively.

Representative John Conyers Jr., the Michigan Democrat who heads the House Judiciary Committee, saw the report as affirmation that the Justice Department had crossed the line in “putting politics where it doesn’t belong.”

“When it comes to the hiring of nonpartisan career attorneys,” Mr. Conyers said, “our system of justice should not be corrupted by partisan politics. It appears the politicization at Justice was so pervasive that even interns had to pass a partisan litmus test. ‘’