Monson entered an Alford plea, which means the defendant does not admit guilt, but will accept a sentence as if he had been convicted due to the amount of evidence likely to convict him in court.
In this case, the evidence was an exact photo of Monson committing the act -- published in an issue of ESPN The Magazine last December.
According to the AP report, prosecutors will recommend that Monson serve a 90-day jail sentence and pay $21,894 in restitution. Monson's sentencing date has been scheduled for Oct. 1.
Monson told The Olympian shortly after the arrest that he spray-painted the anarchist symbol on the government building to protest the war in Iraq and the economic inequality at home and abroad.
The vandalism charge was one of two arrests in 2009. In May, Monson escaped charges of domestic violence and damage of property for a January arrest.
The distractions have not interfered with Monson's fighting career (30-8 overall). He's on a seven-fight win streak with recent wins over Ricco Rodriguez, Sergei Kharitonov and Roy Nelson.