Attorney Michelle MacDonald, the GOP’s endorsed candidate for the Minnesota Supreme Court, was arrested on suspicion of drunken driving and resisting arrest last year, and her case will head to trial this fall, during the general election.

State Republican Party Chairman Keith Downey on Thursday said he was unaware of MacDonald’s 2013 arrest until notified by a Star Tribune reporter. The revelation comes less than two weeks after party delegates in Rochester endorsed MacDonald to run against Justice David Lillehaug.

“None of us, including the convention delegates, were aware of this information about the candidate,” Downey said. “She, of course, is innocent until proven guilty, but at the same time, the delegates did not have the full disclosure they should have.”

He declined to comment on whether the party would withdraw its endorsement. MacDonald, 52, who practices family law, maintains that she was not drinking the night she was pulled over by Rosemount police and is taking the case to trial.

A police report said she refused a field sobriety test and did not take other tests that could have determined her blood-alcohol level.

MacDonald said the GOP’s Judicial Election Committee was aware of the pending case against her. She said that when she told her side of the story, she received near-unanimous support. She has no criminal record in Minnesota.

Downey said that the committee’s nomination of MacDonald came forward “at the last minute” and that in hindsight, the party should have done things differently.

According to court documents, Rosemount police stopped MacDonald, identified in court documents as Michelle L MacDonald Shimota, for speeding at 11:18 p.m. April 5, 2013. The officer testified later that he detected “a slight odor” of alcohol coming from the vehicle and asked her to step out for field sobriety tests. Charges say MacDonald repeatedly refused, saying she hadn’t been drinking, was a “reserve cop” and a lawyer and would walk home. After several minutes, police placed MacDonald under arrest and she “began to physically resist the officers’ attempt to remove her from the vehicle and place her under arrest.”

September trial scheduled

Court documents say police took MacDonald to the Rosemount police station, where she was read the state’s implied consent advisory, which requires those arrested on suspicion of drunken driving to submit to blood, breath or urine testing. She shook her head no when asked if she understood. She then asked to speak with an attorney and was given 34 minutes to contact one, but was unsuccessful.

Asked by officers if she would take the breath test, court documents say, MacDonald never answered the question directly, instead asked to be taken before a judge. Police warned her that not taking a test within the allotted time frame would be considered a refusal, but she never approached the machine. Alcohol levels dissipate over time, so tests taken later wouldn’t reflect the blood level at the time of the arrest. Under state law, admissible blood tests must be taken within two hours of an arrest.

MacDonald was charged with third-degree test refusal, a gross misdemeanor, and fourth-degree DWI and resisting arrest — both misdemeanors. Trial is scheduled for Sept. 15 in Dakota County.

MacDonald says she took her own blood test at a hospital the following morning that showed no alcohol in her system.

She has filed three previous complaints against Dakota County judges and sued one on behalf of a client. She said she’s taking this case to trial because she believes her arrest and prosecution are ­retaliatory.

“When I was being interviewed [by committee members] they were saying this is a good thing because I’ve experienced what people are experiencing on a daily basis,” MacDonald said. “I just never thought this would happen and I’m sucked into a system. Why am I even having to bother with a case where I’ve had zero alcohol, and why am I being asked to go to a trial where they cannot prove anything beyond a reasonable doubt?”

Greg Wersal, a lawyer and failed three-time Supreme Court candidate who introduced MacDonald at the state convention, refused to discuss her case or say whether he was aware of it. Wersal noted that the GOP began endorsing judicial candidates in 1998. The DFL does not endorse judicial candidates.

Bonn Clayton, a party delegate from Chanhassen and member of the Judicial Election Committee who backed MacDonald, said he thought the arrest was a “nonissue,” considering that her blood test showed no alcohol — even though the test was not performed by law enforcement and is not admissible.

“Really, what did she do? She got pulled over, that’s all,” Clayton said. “She didn’t do anything to get pulled over.”

MacDonald, who took the podium at the GOP convention with a Bible and a pledge to uphold the Constitution, said she didn’t think the case would become an issue with voters, but said she’s still prepared to fight it.

“This is no secret,” she said. “I want it out there because it is stupid. I think it’s ridiculous that you would prosecute somebody who has proved their innocence.”

Staff writer Rachel E. Stassen-Berger contributed to this report.