PHILADELPHIA _ President Barack Obama's pitch Wednesday for Hillary Clinton in front of a prime-time Democratic National Convention audience will home in on her temperament to do the job, drawing a contrast from what Obama sees as Donald Trump's lack of fitness to serve as commander in chief.
The night will also serve as the nation's introduction to Virginia Sen. Tim Kaine, announced as Clinton's running mate over the weekend.
In the weeks since he endorsed Clinton, aides say, Obama has talked about how she carried herself as his secretary of State, in particular in the Situation Room during the most sensitive and tense moments of his first term.
He is also guided by his convictions about Trump.
"What I think is scary is a president who doesn't know their stuff and doesn't seem to have an interest in learning what they don't know," he said in an interview broadcast on NBC's "Today Show" on Wednesday.
The argument about Clinton's readiness fits neatly into the bigger case Democrats will make on the convention's third night in Philadelphia, with a lineup that also includes Vice President Joe Biden, former CIA Director and Defense Secretary Leon Panetta and other former military officials.
But the most powerful statement in support of the Democrats' argument 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 Hillary Clinton used as secretary of state. "I think you'll probably be rewarded mightily by our press."
Clinton's campaign reacted swiftly.
"This has to be the first time that a major presidential candidate has actively encouraged a foreign power to conduct espionage against his political opponent," senior policy advisor Jake Sullivan said in a statement. "That's not hyperbole; those are just the facts. This has gone from being a matter of curiosity, and a matter of politics, to being a national security issue."
Trump's own running mate appeared to try to temper the nominee's assertion. Indiana Gov. Mike Pence said that if it were proven that Russia was behind another hack, the one of 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."
Much as Democrats have sought to use this week's convention to positively portray their nominee and the historic nature of her candidacy, Clinton's strongest case for her election has been built around the contrast with her rival. Her campaign has painted him as erratic and running for president in a self-interested pursuit of greater wealth and fame.
Obama will argue 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, plans to echo some of the same themes.
Kaine, known on Capitol Hill for his friendly attitude, who will be formally nominated for vice president on Wednesday, will also try to prove his mettle as someone who can serve in the traditional attack role for running mates.
"There is sure to be some happy warrior elements to his speech because that's part of the reason why he's such a huge value add to the ticket," said Lynda Tran, a Democratic strategist who worked in Kaine's administration as Virginia governor. "That trait in him has proven to be devastating to his opponents in the past. Because as Hillary Clinton said the other day, he comes at you with a smile, but he's got a backbone of steel."
Obama will drive home the idea in the evening's finale, endorsing Clinton as the fierce formal rival who later became one of his most important and trusted advisers.
The president's active role in the race to succeed him has little recent precedent. His approval ratings have hovered around the 50 percent mark for much of the year, boosted somewhat by the public dissatisfaction with the candidates looking to succeed him, White House officials acknowledge.
Obama is not likely to use his speech to shape his own legacy, though much of it rests on whether his successor preserves his administration's actions on climate, foreign policy and other major issues.
Rather, Obama's advisers recognize that the convention is traditionally one of the few moments in a national campaign in which voter sentiments can shift dramatically. Obama will offer his unique perspective to testify as to Clinton's readiness to hit the ground running, particularly on foreign policy.
He'll also, as the first lady sought to Monday, focus on what unites the country _ a coda to the convention speech that launched him on the national scene 12 years to the day when he declared that there were no red states or blue states, but one United States of America.
The White House has been working 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, trusting some of the same officials who helped guide Obama twice to victory.
