Liberal Milwaukee judge Rebecca Dallet trounced conservative opponent Michael Screnock by 12 points in the election, fueling optimism among Democrats for more wins in the midterms. President Donald Trump narrowly won Wisconsin by less than 1 percentage point in 2016.
Walker says the Dallet win shows "we are at risk of a Blue Wave in Wisconsin." He issued a similar warning after a Democrat won a special state Senate election in January.
Walker is up for re-election to a third term in November.
Democrats in Wisconsin are crowing over capturing a state Supreme Court seat — and Republican Gov. Scott Walker is warning of a possible "blue wave" in elections later this year.
Rebecca Dallet, a liberal Milwaukee judge, easily beat conservative Sauk County judge Michael Screnock on Tuesday to win the 10-year term on the court.
The race was nonpartisan in name only, with national figures such as Joe Biden and Eric Holder and groups like the National Rifle Association pouring in money and endorsements.
Wisconsin's Supreme Court races haven't always been reliable predictors of elections later in the year. But Democrats are eager to see momentum, especially after they won a special Senate election in January for a reliably conservative seat in the western part of the state.
Donald Trump carried Wisconsin by a single point in 2016.