Sanders and his wife on his big night in Wisconsin

Democrat Bernie Sanders triumphed over Hillary Clinton in Wisconsin primary, his 7th straight victory against the Democratic frontrunner.  But the Vermont senator faces a mathematically difficult path to the White House.

On the Republican side,  Ted Cruz stormed to a commanding victory, as widely predicted,    denting front-runner Donald Trump’s chances of capturing the GOP nomination before the party’s convention.

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.

U.S. Republican presidential candidate Ted Cruz

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.

At a raucous rally in Wyoming, Sanders cast his victory as a sign of mounting momentum for his campaign.

“With our victory tonight in Wisconsin, we have now won 7 out of 8 of the last caucuses and primaries,” he declared.

The results in Wisconsin make it likely both parties’ primaries will continue deep into the spring, draping front-runners Trump and Clinton in uncertainty and preventing both from fully setting their sights on the general election.

With an overwhelming white electorate and liberal pockets of voters, Wisconsin was favorable territory for Sanders. In a sign of Clinton’s low expectations in the Midwestern state, she spent Tuesday night at a fundraiser with top donors in New York City.

Clinton congratulated Sanders on Twitter and thanked her supporters in Wisconsin. “To all the voters and volunteers who poured your hearts into this campaign: Forward!” she wrote.

Sanders’ win will net him a handful of additional delegates, but he’ll still lag Clinton significantly. With 86 delegates at stake in Wisconsin, Sanders will pick up at least 45 and Clinton will gain at least 31. At the moment, Hillary has 1274 pledged delegates, Sanders 1.025. Hillary also leads Sanders in super delegates, with 469 to 31.

That means Sanders must still win 67 percent of the remaining delegates and uncommitted super-delegates in order to win the Democratic presidential nomination.