The Republicans filed the complaint over comments Gardner wrote from the House floor on Twitter May 8. That day, the House was debating a controversial bill that would have raised taxes.
Gardner wrote entries about Republicans Tom Emmer of Delano and Mark Buesgens of Jordan. The two are among the most confrontational members of the House during floor debates.
In two separate entries, Gardner wrote, "Emmer seems to belittle his female colleagues (rage, sarcasm) on the House floor more than the men? Great face to the GOP?" and, "Why is Buesgens wearing sunglasses? Black eye?"
Emmer and Buesgens filed an ethics complaint against Gardner on May 8.
"I don't understand how many times you can say that you made a mistake and take ownership for your actions."
"Representative Gardner's communications were clearly designed to suggest that his colleagues are physically violent, and prone to harassment of female members of the House of Representatives," they wrote in the complaint.
They added that he violated the spirit and letter of the ethical rules of the Minnesota House of Representatives. They are asking Gardner be properly reprimanded and disciplined.
Buesgens declined comment beyond the written complaint. Emmer didn't return calls.
A spokesman for DFL House Speaker Margaret Anderson Kelliher said Kelliher tried to broker a compromise, which resulted in Gardner apologizing to Emmer and Buesgens personally. Gardner also wrote a letter of apology to every member of the House.
But that compromise apparently was not enough. A Republican official said Emmer and Buesgens want Gardner to apologize on the House floor. Speaker Kelliher declined comment to Minnesota Public Radio News, because the complaint is in the hands of the Ethics Committee.
For his part, Gardner said he doesn't understand what other remedy the two are seeking.
"I don't understand how many times you can say that you made a mistake and take ownership for your actions, and seek a remedy that seeks to resolve the issue," Gardner said. "But that doesn't seem to be enough, and I don't really understand that."
Gardner said he's still working on what he'll tell the House Ethics Committee when it meets on Tuesday to discuss the issue. But he said he'll also provide ample evidence showing Emmer has used offensive speech on the House floor.
Gardner didn't provide full details, but said Emmer has attacked several of his DFL colleagues personally.
"I'm not going to make any excuses for my actions," said Gardner. "But I will point out there has been a preponderance of disrespectful behavior demonstrated, in particular by Representative Emmer, over many months."
"My offensive behavior happened one time, on May 8, and it has ceased," Gardner continued. "And if you watch the House floor on a regular basis, you will see that disrespectful behavior against some of my colleagues has been chronic."
Pressed for an example, Gardner said Emmer has repeatedly mocked House colleagues, citing a fictitious constituent. Gardner says it's obvious Emmer is camouflaging an insult by the way he pronounces the name.
The House Ethics Committee will hold a preliminary hearing on the complaint on Tuesday.
The committee could decide to dismiss the complaint, find probable cause that it merits no further investigation, or call for a further investigation that includes additional hearings.