WAUWATOSA, Wis. — While Ted Cruz decried “gutter politics” against him, former Republican presidential contenders gave him a boost Wednesday, casting the Texas senator as the party’s last best chance to stop Donald Trump. The long and bitter 2016 campaign shifted to a new Midwestern battleground.

Ahead of Wisconsin’s April 5 primary, Gov. Scott Walker, who dropped out of the race last fall, declared that only Cruz can catch Trump as time runs short in the primary season. And former Florida Gov. Jeb Bush gave Cruz his endorsement — a step perhaps designed to hurt Trump more than help the unpopular Texas senator.

“For the sake of our party and country, we must move to overcome the divisiveness and vulgarity Donald Trump has brought into the political arena,” said Bush, who was knocked out of the 2016 contest last month. “To win, Republicans need to make this election about proposing solutions to the many challenges we face, and I believe that we should vote for Ted as he will do just that.”