President Obama forcefully made the case Wednesday that Hillary Clinton has the tenacity, heart and temperament to guide the nation as commander in chief, while painting Donald Trump as a candidate of cynicism and fear unfit for the office.
"There has never been a man or a woman" more qualified to be president than his former secretary of State, Obama declared in his Democratic convention address on a night that also introduced the nation to Clinton's running mate, Virginia Sen. Tim Kaine, who stressed as well that Trump was too risky a gamble.
"Our nation is too great to put it in the hands of a slick-talking, empty-promising, self-promoting, one-man wrecking crew," Kaine said.
In making his case, Obama offered a perspective few else could: experience in the Oval Office.
"Until you've sat at that desk, you don't know what it's like to manage a global crisis or send young people to war. But Hillary's been in the room; she's been part of those decisions," he said. "Even in the middle of crisis, she listens to people, and keeps her cool, and treats everybody with respect."
Obama's active role in the race to succeed him has little recent precedent. He is driven in part by the preservation of his own legacy, much of which rests on whether his successor preserves his administration's actions on climate, foreign policy and other major issues.
Obama dismissed Trump as unworthy of the presidency, saying he wasn't "a plans guy," or a "facts guy."
"He's just offering slogans, and he's offering fear. He's betting that if he scares enough people, he might score just enough votes to win this election," he said. "That is another bet that Donald Trump will lose."
And he targeted Trump's signature promise to "make America great again."
"America is already great. America is already strong. And I promise you, our strength, our greatness, does not depend on Donald Trump," he said.
Obama's and Kaine's arguments fit neatly into the bigger case Democrats made on the convention's third night for Clinton over Trump.
But the most powerful evidence may have come from Trump himself. Earlier Wednesday, he encouraged Russian operatives to hack Clinton's personal emails, a stunning claim from a figure who has long tested credulity and the limits of political discourse.
"Russia, if you're listening, I hope you'll be able to find the 30,000 emails that are missing," he said, referring to deleted emails from the private account Clinton used as secretary of State. "I think you'll probably be rewarded mightily by our press."
Clinton's campaign called it the first time a presidential candidate "has actively encouraged a foreign power to conduct espionage against his political opponent."
"This has gone from being a matter of curiosity, and a matter of politics, to being a national security issue," senior policy advisor Jake Sullivan said.
Former Defense secretary and CIA director Leon E. Panetta said earlier Wednesday to the convention audience that Trump "once again took Russia's side."
"It is inconceivable to me that any presidential candidate would be this irresponsible," he said.
Trump's own running mate appeared to try to temper the nominee's assertion. Indiana Gov. Mike Pence said that if it were proved that Russia was behind another hack into Democratic National Committee emails, with an intent to influence U.S. elections, "I can assure you both parties and the United States government will ensure there are serious consequences."
And in his largely autobiographical speech, Kaine took up the running mate's customary role of attacking the opposition with gusto, contrasting Clinton's detail-laden policy agenda with what he cast as Trump's vague promises.
"He says, 'Believe me,''' Kaine scoffed. "Well, his creditors, his contractors, his laid-off employees, his ripped-off students did just that, and they all got hurt. Folks, you cannot believe one word that comes out of Donald Trump's mouth."
Vice President Joe Biden delivered a similar rebuke, saying that no nominee "has ever known less or been less prepared to deal with our national security."
Clinton's strongest case for her election has been built on the contrast with her rival, though Democrats have sought to use this week's convention to positively portray their nominee and the historic nature of her candidacy. Her campaign has sought to portray Trump as erratic and running for president in a self-interested pursuit of greater wealth and fame.
Obama argued that Clinton will be steady and calm where Trump is unpredictable — another way of saying that he fails the commander-in-chief and chief-executive tests.
Biden, who has worked with Clinton for decades, also sought to undercut Trump's appeal as a champion for the economically distressed in a speech that followed a tribute to his decades of service in the Senate and partnership with Obama.
"This guy doesn't have a clue about the middle class. Not a clue," Biden said of Trump. "Actually, he has no clue, period."
The billionaire was alternately described as a carnival barker, an egomaniac and "a hateful con man," in the words of Senate Democratic leader Harry Reid of Nevada.
"It's time to put a bully racist in his place," said former Maryland Gov. Martin O'Malley, who lost to Clinton in the primaries.
Gov. Jerry Brown took aim at Trump's past suggestion that the warming of the planet was "a hoax."
"Trump is a fraud," he said.
And former New York City Mayor Michael R. Bloomberg, who's been a Republican, Democrat and independent, hit Trump where it hurts: in his business portfolio.
"Trump says he wants to run the nation like he runs his business," Bloomberg said. "God help us."
Obama drove home the idea in the evening's finale, tearing down Trump while endorsing Clinton as the fierce former rival who later became one of his most important and trusted advisors.
Recognizing that the convention is traditionally a moment when voter sentiments can shift dramatically, he wanted to focus on Clinton rather than his own administration.
Obama sees himself as a witness who can describe her in action, especially from the perspective of someone who once fought her himself for the office.
"I came to realize that her unbelievable work ethic wasn't for praise or attention – that she was in this for everyone who needs a champion," he said. "I understood that after all these years, she has never forgotten just who she's fighting for."
Like former President Clinton the night before, Obama sought to convey a portrait of a woman he knew to be far different than her public perception, accused by her critics "of everything you can imagine – and some things you can't."
"She's been there for us – even if we haven't always noticed," he said, as he urged wayward Democrats in particular to put aside their reservations.
"You've got to get in the arena with her, because democracy isn't a spectator sport," he said. "America isn't about 'yes he will.' It's about 'yes we can.'"
Obama, after eight years tempered by trial at home and abroad, said he was ready to "pass the baton." And after a final call to his supporters to "carry her the same way that you carried me," Clinton joined him on stage and offered a warm embrace.
The White House worked closely with Clinton's campaign to prepare for the president's role. White House aides say they have largely deferred to her team in Brooklyn, N.Y., trusting some of the same officials now working for her who also helped guide Obama twice to victory.
As the first lady sought to do in her convention address Monday, Obama also intended to focus on what unites the country — a coda 12 years to the day of the Democratic convention speech that launched his career in national politics when he declared that there were no red states or blue states, but one United States of America.
Memoli and Barabak reported from Philadelphia and Parsons from Washington.
8:50 p.m.: This story was updated with Clinton's appearance.
8:30 p.m.: The story was updated with comments from President Obama.
7:30 p.m.: The story was updated with comments from Vice President Joe Biden and Virginia Sen. Tim Kaine.
6:05 p.m.: The story was updated with comments from Gov. Jerry Brown.
4:50 p.m.: The story was updated with details on convention floor speeches.
3:55 p.m.: The story was updated with Obama's prepared remarks.