Senate Judiciary Committee Chairman Dick Durbin (D-IL) has good reasons to invite Chief Justice John Roberts to testify about Supreme Court ethics reform. But the testimony date should be moved to late summer, not next month.

More importantly, Durbin should make clear in a revised invitation that his intention is not to create a forum for an inquisition in absentia against Justice Clarence Thomas. While recent controversies involving Thomas’s financial disclosures (or lack thereof) have brought the question of high-court ethics to the forefront, the subject should indeed be fair and reasonable systemic reform, not the political targeting of one justice.

Thomas probably erred, not so much by clear law or rule but by an informal ethical obligation to be more transparent. He is making moves to amend his reports, which is good, and probably all that is necessary. Still, the Senate’s job is not to make Roberts answer for Thomas. The Senate’s job — and it absolutely is an appropriate task — is to more broadly protect the integrity of the United States government by insisting on the integrity of its judges and of the highest court in the land.

Thomas’s imbroglio limns a very real, systemic headache. The nine justices are not bound by the Code of Conduct for U.S. Judges that applies to every other judge in the federal system. Some experts argue there are good reasons why not every jot and tittle of that code should apply to the justices. Be that as it may, the lack of clearer, more enforceable rules against the high-court jurists is an obvious problem.

Most evidently, that absence of a more formal code does leave openings for unpunishable corruption, while leaving gray areas that are legitimately confusing to the justices themselves. It also leaves room for public distrust of the court to grow, as is surely happening because of Thomas’ own oversights and the breathless media fulminations against him.

The code should not be filled with petty, niggling regulations meant as political snares against targeted justices. It should not be a cudgel to be used against specific outside organizations. It should not deter judges from making speeches or attending legitimate legal forums. The code should be spare and simple, and unambiguous. And it should be designed so that it in no way infringes upon the necessary independence of the Supreme Court from outside political pressures or skullduggery.

To avoid all those pitfalls will be a tall order.

That’s why it is absolutely appropriate for the chief justice to be invited to testify to Congress, and for him to accept without compulsion. As the chairman of the Judicial Conference of the United States, he essentially provides administrative leadership for the whole federal judicial system. In that role, it is proper for him to provide insights about the special obligations of, and special exemptions for, Supreme Court justices.

What is not proper is for the Senate to demand that Roberts do so while the Supreme Court is still in session, especially in the session’s hectic final two months.

First, just the act of preparing testimony would take him away from the high court’s main focus during its busiest time of the year. Second, the potential for senators to look like they are berating the head of a fiercely and rightly independent branch of government, even as that branch attempts to administer impartial justice according to the Constitution and laws, would be detrimental to the constitutional system. This is especially true when the court is in the midst of considering cases that many senators want to politicize for their own purposes.

The high court, though, is out of session from the beginning of July through the end of September. The court then will have no imminently pending major cases about which senators might feel moved to exert pressure. And Roberts would have time to carefully consider the situation and prepare answers — and, better yet, suggestions for improving the perceptions and reality of court ethics.

Only in a studiously depoliticized atmosphere can a chief justice’s Senate testimony do more good than harm. Done well, though, it certainly could do a lot of good. Hear ye, hear ye.