The Minnesota Supreme Court cleared the way for a defamation lawsuit against state Rep. John Lesch, ruling Wednesday that the St. Paul Democrat is not protected by “legislative immunity” in the case.

The decision upheld a 2019 ruling by the Minnesota Court of Appeals.

Lesch, a nine-term legislator, was sued by St. Paul city attorney Lyndsey Olson after he sent a letter in 2018 to incoming St. Paul Mayor Melvin Carter criticizing her work history and judgment, saying she has a “track record of integrity questions and management problems.”

Lesch had sought to dismiss the suit, arguing in part that he has immunity for his legislative work. He wrote to Carter on Minnesota House of Representatives letterhead under the bold words “PERSONAL AND CONFIDENTIAL.”

But the high court sided with two lower court rulings holding that Lesch’s letter was not related to any pending business before the Legislature and was not sent as part of his legislative duties.

Most of Lesch’s letter focused on the attorney’s office and the decision to hire Olson. Lesch worked in the St. Paul City Attorney’s Office for about 15 years. He is a National Guard member, and he requested documents related to Olson’s hiring process and past work as general counsel for the Minnesota National Guard.