Republican Ted Cruz stormed to a commanding victory in Wisconsin Tuesday, denting front-runner Donald Trump's chances of capturing the GOP nomination before the party's convention.
Bernie Sanders carried the Democratic race over Hillary Clinton, a win that still leaves him with a mathematically difficult path to the White House.
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."
For Sanders, Wisconsin was the latest in a string of victories that have given him an 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 is 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.
For Sanders, Wisconsin was favorable territory, with an overwhelming white electorate and liberal pockets of voters, and the Vermont senator's victory gives him a fresh burst of momentum.
Because Democrats award delegates proportionally, Sanders and Clinton will both emerge from Tuesday's contest with more delegates.
Heading into Wisconsin, Clinton had 1,243 to Sanders' 980 based on primaries and caucuses. When including superdelegates, the party officials who can back any candidate, Clinton holds a much wider lead — 1,712 to Sanders' 1,011. It takes 2,383 delegates to win the Democratic nomination.
Clinton's campaign has cast her lead as nearly insurmountable. Yet Sanders' continued presence in the race has become an irritant for the former secretary of state, keeping her from turning her attention to the general election.
Trump has battled a series of campaign controversies in the lead-up to Wisconsin, including his campaign manager's legal problems following an altercation with a female reporter and his own awkward stumbles in clarifying his views on abortion. Wisconsin's Republican establishment, including Gov. Scott Walker, has also campaigned aggressively against the businessman.
If Cruz wins all of Wisconsin's 42 delegates, Trump would need to win 57 percent of those remaining to clinch the GOP nomination before the July convention. So far, Trump has won 48 percent of the delegates awarded.
To win a prolonged convention fight, a candidate would need support from the individuals selected as delegates. The process of selecting those delegates is tedious, and will test the mettle of Trump's slim campaign operation.