St. Paul City Attorney Lyndsey Olson’s defamation lawsuit against state Rep. John Lesch will head to trial, after a Hennepin County judge denied Lesch’s motion to have the case dismissed.

In a decision filed Wednesday, Judge Frank Magill said Lesch’s arguments for dismissing the case weren’t sufficient. Lesch, a DFLer who represents St. Paul, argued in part that he is protected under the “speech or debate” clause of the Minnesota Constitution, which shields legislators from being sued for things they do in their work as legislators.

“The allegedly defamatory language was not a legislative communication, or act, and thus Defendant’s comments about Plaintiff are not immunized against scrutiny in this suit,” Magill wrote.

Olson’s lawsuit, filed Feb. 16, alleges that Lesch began a campaign to attack her credentials soon after Mayor Melvin Carter announced he was appointing her to the city attorney position.

On Jan. 3, Lesch wrote a letter to Carter on Minnesota House of Representatives letterhead expressing concerns about the mayor’s hiring process for department heads and casting doubt on Olson’s work history. In the letter, Lesch accused Olson of being “a prosecutor who would sacrifice justice in pursuit of a political win — even going so far as to commit misconduct to do so.”

Lesch’s motion to dismiss Olson’s suit also argued that his speech was protected by the First Amendment and that Olson’s complaint failed to specify what exactly Lesch said or wrote that was defamatory.

In his opinion, Magill wrote that the suggestion that Olson committed misconduct on the job is potentially defamatory and not protected by the Constitution. Magill also wrote that Olson’s allegations were laid out clearly in her complaint, which includes a heading labeled “Defendant Lesch’s False and Defamatory Statements.”

“While we are disappointed in the ruling, the court did not rule that Mr. Lesch committed any defamation,” said attorney Marshall Tanick, who is representing Lesch. “He denies doing so, and we intend to vigorously defend the case.”

Lisa Lamm Bachman, Olson’s attorney, said Thursday that she was not surprised by Magill’s decision, which she said is consistent with federal and state case law.

“We’re looking forward to proceeding with the litigation,” she said, “and we’re confident that the truth will come out.”