MINNEAPOLIS  — A state representative who was sued for defamation is not entitled to immunity because comments he made about the St. Paul city attorney were personal or political and not part of any legislative activity, the Minnesota Court of Appeals ruled Monday.

The decision allows Lyndsey Olson’s defamation case against Democratic state Rep. John Lesch to proceed.

Olson sued Lesch after he wrote a January 2018 letter to newly elected St. Paul Mayor Melvin Carter in which he expressed concern about Olson’s fitness for office. Among other things, Lesch alleged that his experience with Olson in the Minnesota National Guard led him to believe she was “a prosecutor who would sacrifice justice in pursuit of a political win — even going so far as to commit misconduct to do so.”

Olson’s lawsuit said Lesch made statements that were false and defamatory.

Lesch asked that the case be dismissed, arguing he had legislative immunity under Minnesota law and under the speech or debate clause in the Minnesota Constitution. But the Appeals Court found that a legislator’s actions must be within the sphere of legitimate legislative activity to warrant immunity.