Karl Rove

WASHINGTON — The House Judiciary Committee pressed its investigation of possible political influence in Justice Department prosecutions on Thursday by issuing a subpoena to Karl Rove, the former chief political operative at the White House.

Rep. John Conyers Jr., D-Mich., the committee chairman, said the subpoena was necessary because Rove had explicitly declined an invitation to appear voluntarily. Conyers and fellow committee Democrats say they want to question Rove about the dismissals of several federal prosecutors and ask whether he knows anything about the decision to prosecute Alabama's former Democratic governor, Don Siegelman.

Siegelman, who had been convicted on a bribery charge, was released from prison in March pending an appeal after an appeals court ruled that he had raised "substantial questions" about his case.

Rove's lawyer, Robert D. Luskin, in a letter to Conyers this week, said the chairman was "provoking a gratuitous confrontation." Luskin asserted that Rove would not appear because he has been directed not to do so by the White House. Although Rove has left the White House and is now a political commentator, Luskin said that Rove "in these matters is not a free agent" and must comply with instructions from the White House not to testify. Conyers has argued that Rove may not himself invoke any privilege on behalf of the White House but that President Bush could do so.

Rove's lawyer also noted that the House committee is engaged in a similar conflict with Harriet E. Miers, the former White House counsel, who has also declined to voluntarily provide testimony about the dismissals of the federal prosecutors and has also defied a subpoena. That issue has landed in federal court and Luskin said the Rove matter should await the resolution of that case.

Conyers, in his letter on Thursday, said that the request to Rove was wider than the one to Miers because it also sought information about the Siegelman prosecution.

Several Democrats have asserted that Siegelman's prosecution was encouraged for political reasons by Republicans in Washington. Siegelman served nine months of a seven-year sentence before being released pending an appeal.

Rove has denied any role in the Siegelman prosecution in comments to journalists but Conyers is seeking to put him under oath. The subpoena demands that Rove appear before the committee on July 10.

If he does not appear, as expected, House Democrats will have to consider issuing a contempt citation as they did for Miers.