MADISON, Wis. (AP) -

The Wisconsin Supreme Court says state law requires repeat drunken drivers to spend at least three years behind bars.

Monroe County Circuit Judge J. David Rice sentenced Clayton Williams of Warrens to three years in prison and three years of extended supervision in 2011 for seventh-offense drunken driving. Rice said the sentencing statutes for seventh, eighth and ninth offenses are murky but he felt they required him to impose a bifurcated sentence with at least three years in prison.

A state appeals court reversed Rice, saying the statues don't require a judge to impose a bifurcated sentence.

The Supreme Court ruled 7-0 Tuesday that the statutes are ambiguous but the history of their development shows they're meant to impose mandatory minimum confinement.

Williams' attorney didn't immediately return a message.