In Minneapolis federal court, the 55-year-old admitted spraying Representative Ilhan Omar with water and apple cider vinegar at a January town hall and is awaiting sentencing.
He told the judge his memory was "fuzzy" and said he did not want anyone to think Omar was in danger; she was unhurt and continued the event.
The attack came amid tense immigration enforcement in Minnesota, and the case highlights rising threats against members of Congress in recent years.
Given the attacker's troubled history, could this assault on a congresswoman have been prevented?
How can public officials balance personal accessibility with the increasing need for security?