An already bitter union battle is getting even nastier in Montgomery County.

The Northeastern-based United Public Service Employees Union and National Correctional Employees Union are trying to take over the county’s largest public employees union — the Municipal and County Government Employees Organization.

They are honing in on Gino Renne, the embattled MCGEO leader, who was arrested recently for allegedly assaulting his wife.

Under a heading labeled, “Leadership: None,” a flier from the two unions says of MCGEO, “Its president is facing 25 years in jail for charges that he assaulted his wife, put a gun to her head, and made statements to her that would disgust anyone.”

Last week, MCGEO parked a rat outside the Maryland offices of the two unions, calling them “scavenger” groups. Renne is expected to return to work next week.