A proposed ban on judges belonging to the Federalist Society and the American Constitution Society is drawing increased attention from Capitol Hill as a Judicial Conference committee is set to weigh next steps for the draft advisory opinion.

Several lawmakers have sent letters to formally weigh in on the proposed opinion, first made public in January. On Monday, Rep. Jim Jordan, recently named the top Republican on the House Judiciary Committee, sent a letter to the Judicial Conference requesting details on its Committee on Codes of Conduct's formulation and consideration of the draft advisory opinion.

In the letter to Sheryl Walter, general counsel for the Administrative Office of the U.S. Courts, Jordan echoed the criticisms of other conservatives on the proposed ban on Federalist Society memberships for federal judges, noting the group does not file amicus briefs in ongoing litigation like the American Bar Association does. The draft rule distinguishes the other groups from the ABA and does not ban judges belonging to that association.

The proposed rule would not stop judges from participating in events hosted by either legal group.

"The Federalist Society describes itself as an organization 'committed to the principles that the state exists to preserve freedom, that the separation of governmental powers is central to our Constitution, and that it is emphatically the province and duty of the judiciary to say what the law is, not what it should be,'" Jordan wrote Monday. "Similar to the ABA, the Federalist Society provides judges and legal scholars with a forum to discuss topics that are central to the improvement of the law and legal profession. There is no rational basis to distinguish the Federalist Society from the ABA on this point."

He asked the Judicial Conference to say why the conduct committee decided to consider banning federal judges from belonging to the legal organizations, hand over materials on the creation of the draft opinion and to say whether any of the judges on the committee are members of the Federalist Society, ABA or ACS. Jordan gave a June 1 deadline for the Judicial Conference to provide the materials, and asked the conference to "be prepared to provide a briefing to the committee about the drafting" of the draft advisory opinion.

News of the draft opinion earlier this year drew scorn from conservatives, who cast it as an unfair block on the Federalist Society compared with the ABA, which itself has been criticized over ratings it has given to some recent judicial nominees. The Federalist Society has played an outsize role in President Donald Trump's judicial nominees, whom the Senate have confirmed at a near-record pace.

Judge Ralph Erickson of the U.S. Court of Appeals for the Eighth Circuit, who chairs the committee behind the draft opinion, said earlier this year that comments from federal judges and other judiciary members on the proposed rule are due by May 20. He said the committee would then "refine or redraft the opinion" accordingly.

Draft advisory rules generally are not made public, and Erickson noted this draft was leaked to media outlets.

The draft rule was also recently raised during the hearing of U.S. District Judge Justin Walker of the Western District of Kentucky last week for a seat on the U.S. Court of Appeals for the D.C. Circuit over a letter he and other federal judges signed opposing the rule, first reported by the New York Times. Walker said at the hearing that Judges Gregory Katsas of the D.C. Circuit and Amul Thapar of the U.S. Court of Appeals for the Sixth Circuit helped draft the letter.

"We believe the exposure draft conflicts with the Code of Conduct, misunderstands the Federalist Society, applies a double standard, and leads to troubling consequences," the letter reads. "The circumstances surrounding the issuance of the exposure draft also raise serious questions about the committee's internal procedures and transparency. We strongly urge the committee to withdraw the exposure draft."

Republican senators, including Senate Majority Leader Mitch McConnell, sent their own letter in March opposing the potential ban, according to the Times.

A coalition of Democratic senators wrote to Erickson and his committee in May in support of the potential advisory opinion, deriding the Federalist Society as being "at the center of a network of dark-money-funded conservative organizations whose purpose is to influence court composition and outcomes." Senate Minority Leader Chuck Schumer joined Sens. Sheldon Whitehouse, Patrick Leahy, Dick Durbin, Sherrod Brown, Richard Blumenthal and Mazie Hirono in signing the letter.

"Judges have long appreciated that with the power of their positions comes the duty to maintain the highest levels of impartiality, both actual and perceived. The draft opinion's findings are based off that core principle. The overheated campaign to influence the committee's deliberative decision-making provides added evidence that this important principle has rarely before faced such pressure," the letter reads.