NEW YORK -- Hillary Clinton laid claim to the Democratic Party's presidential nomination and with it, a piece of history Tuesday night, as she became the first woman to lead a major party's bid for the White House.
Speaking in Brooklyn, New York, on a night where she won the New Jersey primary, Clinton told supporters that they were witnessing a historical moment.
"Thanks to you we've reached a milestone. First time in our nation's history that a woman will be a major party's nominee," she said, adding that the victory "belongs to generations of women and men who struggled and sacrificed and made this moment possible."
She also attacked Republican rival Donald Trump as "temperamentally unfit" to be president of the United States.
Clinton's long-awaited moment of celebration as the first female presumptive nominee of a major political party came as six states held contests that close out a tumultuous presidential primary season.
On Tuesday night, she won the New Jersey, New Mexico and South Dakota Democratic primaries, adding a slew of delegates to her column. Bernie Sanders won the North Dakota Democratic caucus and the Montana primary. California, the delegate-rich prize in Tuesday night's elections, still had not been called for either candidate by 11:45 p.m., but Clinton was leading Sanders by a large margin most of the night.
Clinton addressed the groundbreaking nature of her candidacy in unusually direct terms after spending years avoiding discussions of gender. Her celebration comes eight years to the day after she conceded the Democratic primary race to Barack Obama and lamented the "highest, hardest glass ceiling."
While the spotlight is on the former secretary of state, Democratic rival Bernie Sanders and presumptive Republican nominee Donald Trump also face crucial tests.
Sanders, who won the North Dakota caucuses, faces an existential campaign question. He is grappling with whether to honor his vow to fight on to the Democratic National Convention next month or accept the electoral mathematics that give him no viable path to victory and join Clinton to unite a party divided by a much more competitive primary race than expected.
He'll likely provide more details about his plans during a late-night speech in California. CNN's Brianna Keilar reported that the campaign managers for Clinton and Sanders are in touch, keeping the lines of communication open so they can eventually unify the party, according to a source familiar with the conversations.
President Barack Obama called Clinton on Tuesday night to congratulate her for securing "the delegates necessary to clinch" the Democratic nomination for president. But the president did not formally endorse Clinton. The White House says the president also called Vermont Sen. Bernie Sanders to praise him for shining a spotlight on economic inequality and energizing millions of voters.
The statement said that Sanders requested a meeting with Obama. The meeting is scheduled for Thursday at the White House.
For Trump, the question was how he might extricate himself from the political hole opened up by his controversial comments about a judge of Mexican descent who is overseeing a lawsuit aimed at Trump University.
His accusation that the judge is biased because of his ethnicity has horrified senior GOP leaders who recently reluctantly endorsed him. He tried to neutralize the furor with a statement Tuesday saying his comments had been "misconstrued."
Amid the furor, Trump, who won the Republican contests in New Jersey, New Mexico and South Dakota, delivered a more conventional speech that seemed a departure from the free-wheeling approach he often takes. Using a teleprompter -- notable for someone who has blasted Clinton for being scripted -- Trump attacked Clinton and called for GOP unity.
"We are only getting started and it is going to be beautiful," he said.
He didn't mention the judge during his speech and instead sought to convey that he understood his new role as the leader of the GOP.
"I understand the responsibility of carrying the mantle and I will never, ever let you down," he said.
A top campaign adviser told CNN's Jim Acosta that Trump's speech was "very important to recovering from these five bad days."
The public appearances add up to one of the most consequential set piece moments so far in the presidential campaign, with just as much symbolic importance as the party conventions next month and the three presidential debates in the fall. The speeches will set the trajectory of the general election race and ultimately help decide who wins in November.
Voters went to the polls in New Jersey, New Mexico, North Dakota, South Dakota, Montana and California, which offers the most Democratic delegates of any state.
Clinton reached the magic number of 2,383 delegates needed for the nomination on Monday night after adding the support of several superdelegates.
The former first lady, who has spent a quarter of a century in the national political glare, and weathered a string of controversies, embraced her status as a female icon as never before on Tuesday night, after spending years playing down the historic potential of her career.
Sanders' appearance after polls close in California will be closely watched for signs of his intentions. The Vermont senator was once a fringe political figure, but has used a campaign that electrified the Democratic Party's liberal grassroots to emerge as a major figure.
Sanders has his political legacy and future career to consider, as well as what may turn out to be the last rites of his presidential bid. If he decides that it is the end of the road, Sanders must also encourage his fervent supporters to embrace Clinton -- an experience many may find unpalatable after the euphoria of his unlikely insurgent campaign.
Should Sanders win California, he will strengthen his argument for fighting on after the primary season has officially wound down. But should Clinton triumph in a race that polls suggest could be too close to call, she will put an exclamation point on her victory in the four-and-a-half month primary marathon and the pressure for Sanders to quit could become unbearable.
That pressure is rising almost by the hour, with the White House signaling that President Barack Obama, who remains highly popular among Democrats, is readying an endorsement of Clinton within days.
The Sanders campaign is furious at media organizations, including the Associated Press and CNN, which have declared Clinton as the presumptive nominee based on their own calculations of the intentions of superdelegates --- party officials and lawmakers --- who overwhelming favor the former first lady and New York senator.
The campaign argues that since superdelegates do not officially cast their votes until the convention, naming Clinton as the presumptive nominee is premature.
"If you don't have 2,383 in pledged delegates you go to the convention and the super delegates will decide," said Sanders campaign manager Jeff Weaver on CNN. "Even though somebody may be ahead, they have not won if they don't have 2,283 in pledged delegates."
Given the state of the race, it is unlikely Clinton will reach that threshold on pledged delegates alone after the six state races and the District of Columbia primary in a week's time. Still, Clinton will likely capture a majority of pledged delegates -- a milestone that would further hike pressure on Sanders to admit defeat and join her in uniting the Democratic Party to take on Trump.
Democratic strategist Bill Burton predicted that the forces of political gravity would soon begin to take effect. Even if Sanders doesn't immediately drop out, he said, " there is going to be a coalescing of support around Hillary."
"You'll see a large chunk of his supporters start moving away from him, just because people get that the stakes are high here," said Burton, who was Obama's national press secretary during his 2008 campaign. "We're moving toward a general election where if we don't start coalescing -- we're losing days to take this fight to Donald Trump."