Arlen Specter, a U.S. senator from Pennsylvania from 1981 to 2011, was chairman of the Senate Judiciary Committee from 2005 to 2007.

The subject of judicial recusal has attracted attention, focused on Justices Clarence Thomas and Elena Kagan, as the Supreme Court argument on Obamacare draws closer. Chief Justice John G. Roberts Jr. implicitly acknowledged this question in his 2011 year-end report when he defended, without explicitly naming them, the propriety of their sitting.

The court’s recurrent 5 to 4 ideological split has shaken confidence in its integrity, which is indispensable for maintaining the rule of law. The 2000 decision in Bush v. Gore, in which the justices elected George W. Bush by one vote with a tortured interpretation of “threaten[ed]irreparable harm,” has not been forgotten. The court is still reeling from public reaction to its 2010 decision in Citizens United v. Federal Election Commission, which overturned hundred-year-old precedents in allowing corporations and unions to make unlimited and anonymous campaign expenditures. Enormous expenditures from political action committees have turned the Republican presidential primaries into a billionaires’ auction and threaten to enable big money to elect our next president.

Kagan’s participation in the health-care case has been challenged because she was solicitor general in the Obama administration when the Affordable Care Act was passed. Thomas’s impartiality has been questioned because his wife has been an outspoken critic of that legislation.

This follows a public request from Common Cause Chief Executive Bob Edgar, a former U.S. representative from Pennsylvania, to Attorney General Eric H. Holder Jr. that the administration seek to vacate the judgment in Citizens United. Edgar’s reasons include that Thomas should have stepped aside because of federal law requiring a justice not to participate when “he knows that . . . his spouse . . . has a financial interest in the subject matter in controversy.” Virginia Thomas reportedly had such an interest in her PAC, which benefited from the Citizens United decision.

Critics of both justices have drawn support from a letter that 138 law school professors sent to the chairmen of the House and Senate judiciary committees and a petition bearing 100,000 signatures lobbying the Supreme Court for a procedure to review a justice’s refusal to recuse. They rely on the high court’s 2009 decision in Caperton v. A.T. Massey Coal Co. Inc., which said that due process was violated by a West Virginia Supreme Court justice who refused to recuse himself from a case involving a major campaign contributor.

Starting with the 17th-century principle from Lord Coke that “no man can be a judge in his own case,” Justice Anthony M. Kennedy wrote in the Caperton decision that a judge “accused of bias” should not be “the sole trier of fact” on “inquiring into actual bias.” Why wouldn’t that rationale apply equally to require review of a Supreme Court justice’s decision to sit under questionable circumstances, at least a review by his or her colleagues?

Roberts’s year-end writing argues against disqualification on the ground that an eight-person court would be unable to decide cases in the event of a 4 to 4 split. That problem is solvable by a suggestion that Justice John Paul Stevens made during a meeting we had in his chambers on April 29, 2010 — to have a retired justice replace the absentee. In any event, a 4 to 4 vote that results in no decision is preferable to a tainted decision. Roberts also wrote that the individual justice should remain the sole decider on participation because the Constitution created the Supreme Court without any review for its decisions. Yet the court itself could structure a review process.

Because recusal motions are rare, the challenged justice could be required to write an opinion that gives his or her reasons for not stepping aside. As New York University professor Stephen Gillers has suggested, the motion and opinion could be reviewed by the chief justice or, if the chief is involved, the senior associate justice. If the reviewing justice found the challenge meritorious, the issue would be referred to the full court, absent the justice in issue, for a ruling by the majority with a written opinion.

Congress has established standards in which federal judicial officers must disqualify themselves without any exception for the Supreme Court. As Roberts pointed out in his year-end report, “the limits of Congress’ power to require recusal have never been tested.” But if the court does not act, Congress should. Although the Supreme Court could always have the last word, it would be wise to act on its own initiative to provide transparency and assure the public of the justices’ impartiality and integrity.