Rand Paul that broke the lawmaker's ribs.
The Kentucky man who tackled Sen. The charge carries maximum penalties of 10 years in prison and a $250,000 fine.
The sentencing date has been set for June 15.
Prosecutors have said they are looking at pushing a 21-month jail sentence on Boucher, after he attacked Paul outside of his home in Bowling Green, Ky., which left the senator with six broken ribs, pleural effusion and pneumonia.
Boucher at first pleaded not guilty in November.
In November, Boucher's attorney said the altercation between his client and Paul resulted "over a trivial matter".More news: Celtic boss Brendan Rodgers turns the screw on rivals Rangers
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Baker said he will argue for Boucher to be placed on probation.
Boucher has agreed to pay an undisclosed amount to Paul as restitution. A close friend of Paul's said the Republican senator had gotten off his riding lawn mower to remove a limb when he was tackled from behind.
The two had an ongoing dispute over yard maintenance for a few months. Paul has said he never saw the attacker because he was facing downhill and wearing ear protection from the noise of his lawn mower.
He also characterized the attack as a dispute that boiled over that had nothing to do with politics.
Battani allowed Boucher to remain free on a $25,000 unsecured bond ahead of his sentencing, and ordered him not to have any contact with the senator or his family.