Philadelphia (CNN) The Democratic A-list on Wednesday cast Donald Trump as a threat to the American dream -- and Hillary Clinton as the nation's only chance to save it.

President Barack Obama called Trump a "homegrown demagogue." Michael Bloomberg dismissed him as a "con." And Vice President Joe Biden, in rejecting Trump, declared that "Americans have never, ever, ever, ever let their country down."

They set the frame for the Democratic National Convention's most important moment: Clinton's speech Thursday night.

Here are six takeaways from the third night in Philadelphia:

Obama: 'the America I know'

Obama cast the 2016 election as a choice between two visions for the country: The one he described on the Democratic convention stage when he rocketed to stardom 12 years ago in Boston against a dark and dystopian view from Trump that Obama said doesn't match "the America I know."

"It's not just a choice between parties or policies; the usual debates between left and right," he said. "This is a more fundamental choice -- about who we are as a people, and whether we stay true to this great American experiment in self-government."

In a direct shot at Trump, Obama said: "Our power doesn't come from some self-declared savior promising that he alone can restore order as long as we do things his way."

If Democrats wanted to frame the election as their optimism against Trump's darkness, the Republican nominee was eager to help. As Obama spoke, Trump's campaign emailed reporters a statement with the subject line: "OWNING THE 3RD TERM: VIOLENT CRIME RISING ACROSS THE COUNTRY."

Obama passes the baton

Obama sought to lend Clinton every ounce of credibility he has, telling delegates that no man or woman has ever been better-qualified for the presidency than his former secretary of state.

"Not me, not Bill, not nobody," he said.

Bill Clinton stood and applauded -- two Democratic icons at once saying: This is Hillary Clinton's party now.

From a video introduction that focused on the work left to do to achieve Obama's vision, the President made clear that Clinton is the only person capable of solidifying his legacy.

"I have confidence, as I leave this stage tonight, that the Democratic Party is in good hands," Obama said as he closed.

Even Obama's final line was designed to underscore his vision of Clinton as his heir. "Thank you for this incredible journey," he said. "Let's keep it going."

Obama got as close to a literal hand-off as possible, with Clinton joining him on-stage as soon as he finished his speech. The two held hands and waved, and then both Clintons and Obama met privately off-stage.

Joe Biden's pep rally for America

Want to know what Vice President Joe Biden would have brought to the 2016 presidential campaign, had he decided to run? Rewind his 12-minute speech Wednesday night.

His 12-minute speech was half anti-Trump and half pep rally for the middle class.

"He is trying to tell us he cares about the middle class. Give me a break. That's a bunch of malarkey," Biden said. "This guy doesn't have a clue about the Middle Class. Not a clue."

In what might've been Biden's swan song, Biden -- or "middle-class Joe," he called himself -- made an argument that could penetrate Trump's base of supporters in a way Clinton and Obama can't.

"Biden just did what Obama and Clinton don't do effectively...he evangelized American Exceptionalism," tweeted Rob Stutzman, a California Republican strategist.

Tim Kaine: America's dad

His job was never going to be easy: Vice presidential nominee Tim Kaine was up after Biden had brought down the house and while the crowd was eagerly anticipating Obama.

Kaine wasn't chosen by Clinton to light up a room. On social media, Kaine was compared to a dad: Slightly embarrassing, yet relentlessly nice, even when he was trying to be mean. He even did an impersonation, mocking Trump with the billionaire's reprise "believe me."

"By the way, does anybody in this massive auditorium believe that Donald Trump's been paying his fair share of taxes?" Kaine asked. And the crowd roared "No!"

He built toward a strong close, name-checking a list of icons of the progressive movement. And his biggest applause lines came in Spanish -- a reminder of his fluency in the language, which could help the Democratic ticket reach Latino voters who Trump might have alienated.

Bernie-or-busters' myopia

Democrats have largely been able to snuff out any real damage from the Bernie-or-bust crowd -- but their chants over former Secretary of Defense Leon Panetta blew a moment the party had planned all day.

Panetta was the designated hitter on the controversy over Donald Trump's suggestion that Russia release Clinton's emails. And he dropped a couple sharp lines as he made the broader case that Trump is unfit to lead the nation's military.

"As someone who was responsible for protecting our nation from cyber-attacks, it is inconceivable to me that any presidential candidate would be that irresponsible. I say this out of a firm concern for the future of my children and my grandchildren: Donald Trump cannot become commander-in-chief," Panetta said.

Yet the Bernie-or-busters stepped all over the moment by chanting "No more wars!" over him. It was bad enough that Democrats had to dim the lights over the rebelling delegations to try to get back on-message. Afterward, television anchors focused on the protests -- not Panetta's anti-Trump message.

Bloomberg: Trump's a 'con'

Former New York City Mayor Michael Bloomberg -- the Democrat-turned-Republican-turned-independent curiosity of the Acela corridor -- delivered a billionaire-on-billionaire assault on Trump's business record.

He quipped that unlike Trump, he didn't start his business empire with a "million-dollar check from my father."

Bloomberg, who mused about an independent run for president himself, endorsed Clinton -- but, as one of the few political figures with the business experience to match Trump's, he was most effective undermining the core selling point of Trump's candidacy: His competency, compared to the political establishment's ineptitude.

"Trump has left behind a well-documented record of bankruptcies, thousands of lawsuits, angry shareholders and contractors who feel cheated, and disillusioned customers who feel ripped off," Bloomberg said. "Trump says he wants to run the nation like he's run his business. God help us."

"I'm a New Yorker," he said. "I know a con when I see one."