WASHINGTON — The House of Representatives Judiciary Committee on Thursday subpoenaed former White House Political Director Karl Rove to force him to testify about allegations that he and other political operatives pressured the Justice Department to prosecute Southern Democrats.

Rep. John Conyers, D-Mich., the committee chairman, issued the subpoena after weeks of icy correspondence with Rove's lawyer, who argued Rove is covered by executive privilege and doesn't have to testify. Attorney Robert Luskin said Rove would agree only to answer questions in writing or in an off-the-record session that isn't transcribed.

Rove, a central figure in the controversy that led to last year's resignation of Attorney General Alberto Gonzales and other Justice Department officials, departed last year after President Bush first told the Senate Judiciary Committee he would invoke executive privilege to block a congressional subpoena.

The House committee wants to ask Rove about an array of allegations of political influence in the Justice Department, among them charges that former Alabama Gov. Don Siegelman, a Democrat, former Mississippi Supreme Court Justice Oliver Diaz and others were targeted for prosecution. Internal Justice Department watchdogs also are investigating the allegations.

Conyers' committee has sued in federal court to challenge President Bush's claim of executive privilege for White House chief of staff Joshua Bolten and former White House counsel Harriet Miers, who were cited for contempt-of-Congress charges when they followed Bush's guidance and refused to testify. The committee sought their appearances as part of its inquiry into the firings of nine U.S. attorneys whose ousters triggered the scandal.

White House spokesman Tony Fratto said that the committee already knows that Rove is covered by an executive privilege claim and can't testify, though Rove has offered to assist the panel in other ways.

"They know he can't respond to those questions, but they want their political theater," Fratto said. "We'll review the subpoena, assess its relationship to currently pending matters and respond at the appropriate time and in the appropriate forum."

Although it isn't enshrined in the Constitution, executive privilege is a power that presidents often have invoked to shield themselves and other members of the executive branch from what they consider unwarranted intrusions by the other two branches of government, Congress and the courts.

Conyers first wrote to Rove on April 17, 10 days after Siegelman charged on CBS' "60 Minutes" that Rove and other Republicans had tried to destroy his political career and precipitated his 2006 conviction on charges of bribery and obstruction of justice. Siegelman, who recently was released from prison pending an appeal, called on congressional committees to seek Rove's testimony.

Conyers cited an affidavit from Alabama lawyer Jill Simpson recounting a 2002 conference call in which Bill Canary, the husband of U.S. Attorney Leura Canary of Montgomery, Ala., purportedly said that Rove had talked to the Justice Department about pursuing Siegelman. Bill Canary was an adviser to Bob Riley, the Republican gubernatorial challenger who at the time was locked in an election recount with Siegelman, a recount that Riley won.

Conyers' letter noted that in an interview with GQ magazine, Rove had dismissed Simpson as a "complete lunatic" who had never mentioned his name. Conyers said that Rove was mentioned several times in the affidavit.

Texas Rep. Lamar Smith, the Judiciary Committee's ranking Republican, accused committee Democrats of "partisan games" in subpoenaing Rove and said he would demand that Simpson testify at the hearing about her "unfounded accusations."