IMPEACH BUSH

WASHINGTON, Oct. 23 — Richard L. Thornburgh, attorney general in the Reagan and first Bush administrations, charged Tuesday that political reasons motivated the Justice Department to open corruption investigations against Democrats in Mr. Thornburgh's home state, Pennsylvania.

In testimony before the House Judiciary Committee, Mr. Thornburgh became the first former Republican attorney general to join with Democratic lawmakers to suggest that the Justice Department under Attorney General Alberto R. Gonzales had singled out Democratic politicians for prosecution.

"The citizens of the United States must have confidence that the department is conducting itself in a fair and impartial manner without actual political influence or the appearance of political influence," said Mr. Thornburgh, who is now in private practice. He is defending the former elected Democratic coroner of Allegheny County, Pa., against federal corruption charges. "Unfortunately that may no longer be the case."

His unusually harsh criticism of fellow Republicans was directed specifically at the United States attorney in Pittsburgh, Mary Beth Buchanan, who was director of the Executive Office of United States Attorneys, based in Washington, in 2004 and 2005. That office has come under scrutiny for its role in the dismissal of United States attorneys last year, in some cases for what appear to have been partisan reasons.

"It has been and remains the practice of the United States Attorney's Office to investigate and prosecute individuals who violate federal law without regard to their political affiliation," Ms. Buchanan said in a written statement.

Mr. Gonzales, who stepped down last month, and his former Justice Department colleagues have repeatedly denied that politics played any role in the prosecution of corruption cases in the Bush administration. The department's inspector general is now conducting an investigation of the reasons for the firings of the United States attorneys last year.

The House Judiciary Committee is investigating the Justice Department's handling of the prosecution of several prominent Democrats around the country, most notably the prosecution and conviction of former Gov. Don Siegelman of Alabama on federal corruption charges. A Republican lawyer there has given a sworn statement to the committee in which she said she overheard discussion of how the White House had put pressure on local prosecutors to pursue the case.

Mr. Thornburgh noted that Ms. Buchanan had conducted a series of high-profile corruption investigations against Pennsylvania Democrats in the months before the 2006 midterm elections, including the one against the former coroner, Cyril Wecht.

"During this same period, not one Republican officeholder was investigated and/or prosecuted by Ms. Buchanan's office — not one," Mr. Thornburgh said, noting that there had been accusations of corruption against two prominent Republican members of Congress from Pennsylvania in that same period. He said that Dr. Wecht, a nationally prominent forensic pathologist, "would qualify as an ideal target for a Republican U.S. attorney trying to curry favor with a department which demonstrated that if you play by its rules, you will advance."

Dr. Wecht, who is scheduled to go on trial next year, has been charged with 84 criminal counts, including theft and mail fraud, much of it involving his use of a government fax machine and postage meter. Mr. Thornburgh described the prosecution as "bizarre."

Mr. Thornburgh's testimony drew harsh attacks from Republicans on the Judiciary Committee who accused him of trying to undermine the credibility of the Justice Department in an effort to help a client.