(Photo: Diego M. Radzinschi/NLJ.)

A bipartisan group of congressional leaders filed court papers Tuesday defending the constitutional shield that protects members of Congress and their staff from being forced to provide information about legislative activities.

The Bipartisan Legal Advisory Group of the U.S. House of Representatives filed the amicus brief in the U.S. Court of Appeals for the Ninth Circuit, where former U.S. Rep. Rick Renzi, R-Ariz., is challenging his conviction on public corruption charges.

A federal jury in Arizona found Renzi guilty in June 2013 of extortion and bribery in connection with a federal land swap. He was sentenced to three years in prison. As part of his appeal, Renzi’s lawyers at Mayer Brown and Steptoe & Johnson LLP argue prosecutors violated the “speech or debate” constitutional protection by questioning one of his former aides.

At the same time, Renzi is challenging the trial judge’s decision to apply the protection to another ex-congressional aide Renzi wanted to question. He said the judge should have balanced his rights as a defendant with the protection.

The Bipartisan Legal Advisory Group’s brief urges the appeals court to adopt a broad reading of the protection. The group agreed with Renzi that prosecutors violated the clause by questioning his former aide, but disagreed with his balancing argument concerning the other witness.

The group said it wasn’t defending Renzi’s actions, but said his appeal raised issues involving the speech-or-debate clause “that are of substantial institutional concern to the House.” (Emphasis in original.)

The U.S. Supreme Court stated “unequivocally that when the speech-or-debate clause applies—that is, when a member is acting within the ‘legislative sphere’—the protections are ‘absolute,’ ” House General Counsel Kerry Kircher wrote in the group’s brief.

The House brief said prosecutors shouldn’t have been allowed to question one of Renzi’s former aides about their conversations concerning legislation. Discussions between Renzi and the aide about the federal land-exchange legislation at the heart of his criminal case were privileged, the group argued.

“Renzi’s motivations for his decisions regarding the [land-exchange bills]—good, bad, or otherwise—are off limits,” Kircher wrote.

However, the group disagreed with Renzi that the trial judge should have balanced Renzi’s right to present a defense with the speech-or-debate clause protection afforded to another witness—a former congressional aide to both Renzi and former Arizona congressman Jim Kolbe—who Renzi wanted to question.

Unlike executive privilege, which can be qualified, Kircher wrote, the speech-or-debate clause “is absolute when it applies and, therefore, ‘there is no balancing of interests.’”

The Ninth Circuit isn’t the only federal appeals court considering the scope of the speech-or-debate clause. Fraser Verrusio, a former congressional staffer convicted on corruption charges in the Jack Abramoff scandal, has also argued that his rights as a defendant should be balanced with the clause’s protections. Verrusio appealed his conviction on a number of grounds, including challenging the trial judge’s decision to quash his subpoena for testimony from a former congressional staffer.

The U.S. Court of Appeals for the D.C. Circuit heard arguments in Verrusio’s case in November and hasn’t released its decision. During arguments, Judge Brett Kavanaugh said he understood the protection to be “absolute.”

The Ninth Circuit is scheduled to hear arguments in Renzi’s case the week of June 16. Renzi is free pending his appeal.

Contact Zoe Tillman at ztillman@alm.com. On Twitter: @zoetillman.