House Judiciary Chairman John Conyers (D-Mich.) suggested in a hearing on the U.S. attorney firing scandal today that his committee may have to act on contempt of Congress motions if the White House does not respond to outstanding subpoenas.

“It is possible enforcement action may need to be taken,” Conyers said, explaining that a contempt citation “may be the next likely step” if the White House refuses to comply with subpoenas issued last week by both chambers for documents and testimony by ex-White House counsel Harriet Miers and former White House political director Sara Taylor.

The first deadline for compliance is June 28. Conyers said there would be no enforcement action or contempt action this week.

Meanwhile, the Senate Judiciary Committee on Thursday morning voted, 13-3, to authorize subpoenas for White House and Justice Department legal opinions surrounding the National Security Agency’s warrantless wiretapping program.

On the House side, Conyers made the statement regarding contempt citations during a hearing of the Judiciary subcommittee on commercial and administrative law featuring outgoing Deputy Attorney General Paul McNulty. Conyers asked whether McNulty would help Justice Department officials bring charges of criminal contempt against White House officials who refuse to testify or provide documents related to the prosecutor purge.

McNulty demurred in answering the question, saying he had been recused from decisions about providing Justice Department witnesses and documents to Congress because of his role in the scandal.

McNulty also said the reason he did not object to New Mexico prosecutor David Iglesias being on the hit list was because of an Oct. 4 phone call from Sen. Pete Domenici (R-N.M.) criticizing Iglesias’ performance.

For the first time, Conyers today intimated Democrats may be willing to enter a feisty legal battle if the White House flouts the subpoenas. If the House passes a contempt motion — a rare occurrence — the matter would, ironically, be referred to the U.S. attorney of the District of Columbia. Attorney General Alberto Gonzales would then be charged with enforcing the motion.

Meanwhile, McNulty sought to downplay any conflicts between his February Senate testimony and testimony last month before the House by former top Justice aide Monica Goodling.

“No one in particular misled me when I was trying to get ready for my interview,” McNulty said, referring to a Feb. 14 private Senate testimony.

McNulty said he was “very accurate and truthful” when he told the Senate that the White House had approved the list of prosecutors to be fired. Goodling suggested that McNulty’s testimony was less than accurate on that point.

McNulty did not dispute the characterization that he was “out of the loop” during the process of selecting the eight prosecutors put on the hit list during 2006. He said the first time he heard about such a list was in October 2006 and that he recommended one name, which has remained anonymous, be removed.

McNulty said he did not speak directly with Gonzales about the list until Dec. 7, when the federal prosecutors were fired. But McNulty was present at a Nov. 27 meeting in which the list was discussed.

Conyers and subcommittee Chairwoman Linda Sánchez (D-Calif.) said after the hearing that McNulty had not been totally straightforward.

“He has walked a thin line between Attorney General Gonzales and not getting him into too much difficulty and trying not to antagonize Monica Goodling,” Conyers said. “In the end, this was not a fully candid discussion we had.”

Democrats have been pursuing a wide-ranging probe into why nine federal prosecutors were fired in 2006, believing it was done for political reasons at behest of the White House. Justice and administration officials dispute this and argue the firings were totally legitimate.