“She believes you’re a Democrat and doesn’t feel you can be trusted.”

WASHINGTON, May 11 — Two years ago, Robin C. Ashton, a seasoned criminal prosecutor at the Department of Justice, learned from her boss that a promised promotion was no longer hers.

“You have a Monica problem,” Ms. Ashton was told, according to several Justice Department officials. Referring to Monica M. Goodling, a 31-year-old, relatively inexperienced lawyer who had only recently arrived in the office, the boss added, “She believes you’re a Democrat and doesn’t feel you can be trusted.”

Ms. Ashton’s ouster — she left the Executive Office for United States Attorneys for another Justice Department post two weeks later — was a critical early step in a plan that would later culminate in the ouster of nine United States attorneys last year.

Ms. Goodling would soon be quizzing applicants for civil service jobs at Justice Department headquarters with questions that several United States attorneys said were inappropriate, like who was their favorite president and Supreme Court justice. One department official said an applicant was even asked, “Have you ever cheated on your wife?”

Ms. Goodling also moved to block the hiring of prosecutors with résumés that suggested they might be Democrats, even though they were seeking posts that were supposed to be nonpartisan, two department officials said.

And she helped maintain lists of all the United States attorneys that graded their loyalty to the Bush administration, including work on past political campaigns, and noted if they were members of the Federalist Society, a conservative legal group.

By the time Ms. Goodling resigned in April — after her role in the firing of the prosecutors became public and she had been promoted to the role of White House liaison — she and other senior department officials had revamped personnel practices affecting employees from the top of the agency to the bottom.