Ted Cruz pulled off two striking Super Saturday victories to bolster his case that he is the only viable Republican alternative to Donald Trump while Democrat Bernie Sanders also scored a pair of morale-boosting wins.
The Cruz victories could raise questions about whether GOP voters are reassessing their views of Trump after a week of racially-charged controversies and a debate performance dominated by vulgar innuendo.
Still, Trump and Hillary Clinton recorded their own important victories to increase their delegate counts and cement their control over the 2016 race.
"I have been in competitions all of my life," Trump said in a news conference at Trump International Golf Course in West Palm Beach, Florida. "There is nothing so exciting as this stuff."
Cruz notched twin victories in Kansas and Maine, Sanders won Kansas and Nebraska, and Clinton and Trump won the night's big prize: delegate-rich Louisiana. Trump will also win the Kentucky Republican caucuses, CNN projects, where he and Cruz faced off in a tight race.
"God bless Kansas. And God bless Maine," Cruz said, and argued that his performance Saturday represented an important pivot point in the GOP race.
"What we are seeing is Kansas is a manifestation of a real shift in momentum," Cruz told reporters in Idaho where he had a campaign event. He again asked rival candidates to "prayerfully" consider whether they had a path to victory as he sought to unite opposition to Trump.
Trump lobbed criticism at his GOP rivals.
He said Rubio had a "very, very bad night" and called on him to drop out of the race. And he took at shot at Cruz, after spending months saying the Texas senator is ineligible to run for President because he was born in Canada.
"He should do well in Maine because it is very close to Canada," Trump said.
It was another grim night for Rubio, who has so far won only one of the 18 contests in the GOP race, despite billing himself as the only candidate with the potential to unify the Republican Party and the broad appeal needed to beat Clinton.
While Kansas may represent too small a sample to validate Cruz's claims, it is clear that his win will be parsed for signs that it represents the stirrings of a backlash against Trump, after the billionaire became embroiled in a controversy he was slow to repudiate the Ku Klux Klan, and introduced a vulgar note into a Republican debate Thursday night.
On the other hand, the victory by Cruz in Kansas appears to fit squarely into historical precedent. Like Cruz, the previous two victors of that state's GOP contests, Rick Santorum in 2012 and Mike Huckabee in 2008, had strong appeal among evangelicals which they had also demonstrated by winning the Iowa caucuses.
Despite his win Saturday in Maine and Tuesday in Alaska, there are still doubts about whether Cruz can expand his appeal beyond hardcore conservatives in a national race.
Super Saturday voting is happening in the wake of former Republican nominee Mitt Romney's assault on Trump, which ignited a civil war within the GOP between establishment figures and the billionaire's army of angry 'outsider' voters.
On the Democratic side, Clinton is looking to further cement her lead over her challenger Sanders, though the Vermont senator had an advantage in the fact that the contests in Kansas and Nebraska are caucuses, a format in which he has tended to perform better than primaries during the 2016 campaign.
Sanders' wins in the caucus states could offer him a boost after he was overshadowed by Clinton on Super Tuesday. But they also appear to underline that Sanders is stronger among largely white, less diverse electorates. That is a problem for Sanders because the nomination could be decided by the large numbers of minority voters in the Democratic electorate, to which Clinton has demonstrated she has more appeal.
Clinton's campaign also worked in both states to narrow the margin of her defeat, learning the lessons from the 2008 campaign when Barack Obama piled up large delegate counts in caucus states. At the end of the night, her deficit to Sanders in Kansas and Nebraska is likely to be limited.
The Super Saturday contests offer a chance for the two front-runners to quicken their momentum after they both came out of the contests last Tuesday with solid delegate leads. They still face major battles in crucial elections in Michigan, Ohio and Florida over the coming weeks.
Clinton has a lead of about 200 pledged delegates over Sanders, while Trump leads Cruz by around 100 delegates and is about 200 delegates ahead of the third place candidate Rubio.
Rubio put on a brave face, saying that the states being contested on Super Saturday favored other candidates, but predicted that his fortunes would soon change. He predicted victory in his home state of Florida on March 15.
"The map only gets friendlier for us after tonight," Rubio told reporters during a trip to Puerto Rico, which holds a Republican primary on Sunday. "There will be more delegates awarded in Florida than basically every state that voted tonight combined."