MADISON, Wis. — Some of the sharpest First Amendment minds in the country are weighing in on a Wisconsin-based civil rights case that is testing the boundaries of prosecutors’ power and the protections of free speech.

In advance of next week’s oral arguments before the 7th Circuit U.S. Court of Appeals, at least five former Federal Election Commission members, including four former chairpersons, have filed amicus briefs with the court in support of the conservative targets of a sweeping and politically charged John Doe investigation.

The commissioners, including Lee Ann Elliott, David Mason, Hans von Spakovsky, Darryl Wold and Bradley Smith, have submitted two requests to intervene in the appeal, sought by John Doe prosecutors, now defendants in a civil rights lawsuit filed by conservative activist Eric O’Keefe and the Wisconsin Club for Growth.