Trump's defeat capped one of the worst periods of his campaign, a brutal stretch that highlighted his weaknesses with women and raised questions about his policy depth. While the billionaire businessman still leads the Republican field, Cruz and an array of anti-Trump forces hope Wisconsin signals the start of his decline.
"Tonight is a turning point," Cruz told cheering supporters at a victory rally. "It is a call from the hardworking people of Wisconsin to America. We have a choice. A real choice."
Cruz, a Texas senator with a complicated relationship with Republican leaders, also cast his victory as a moment for unity in a party that has been roiled by a contentious primary campaign.
But Trump was unbowed. His campaign put out a biting statement: "Ted Cruz is worse than a puppet — he is a Trojan horse, being used by the party bosses attempting to steal the nomination from Mr. Trump."
Sanders's sweeping win in virtually every county in Wisconsin, except Milwaukee, gives him greater incentive to keep competing against Clinton. But he still trails her in the pledged delegate count and has so far been unable to persuade superdelegates— the party officials who can back any candidate — to drop their allegiance to the former secretary of state and back his campaign.