Barack Obama has delivered a stark and dramatic warning to Americans: Our democracy is in immediate peril.
Call this Obama's Defcon 1 moment.
After four years of near silence, America's 44th President opened fire with everything he had. And then some.
The protocol is that former American presidents do not publicly criticise the current occupant of the Oval Office.
Along with the political norms that Trump has shredded, that tradition has overnight been ripped up as well.
Obama: Our democracy is at stake
Barack Obama was speaking on the third night of the Democratic Party's virtual, online convention.
Significantly, he delivered his grave warning not from Washington DC, where he lives. Or from Delaware, the home of Joe Biden.
He chose Philadelphia, the birthplace of American democracy, and where the country's foundational documents were composed.
Obama did more than raise a red flag about what he perceives as Trump's reckless disregard for voting rights.
He directly warned that his successor would destroy democracy in order to win in November.
One of Joe Biden's biggest tasks ahead of the election will be mobilising those who got behind Barack Obama when he was elected and also progressives, says Washington Correspondent Robert Moore
He went on in his primetime speech to lacerate President Trump's character and values, saying that he has treated the "awesome responsibility" of his office to help only himself and his friends, and "as one more reality show that he can use to get the attention he craves".Brutal stuff.
Amid all of that, the party's vice presidential nominee introduced herself to the country.
Senator Kamala Harris spoke of her immigrant background, she lavished praise on Joe Biden, and emphasized the stakes in November.
It was a polished, impressive, even emotional moment that will give Democrats further hope that they can win the White House by recreating the Obama voter coalition of 2008 and 2012.
But it is Obama's warning that will dominate the headlines.
Furthermore, it is certain to trigger a fierce counter-assault from Donald Trump.
This election campaign is now up and running. And it is being framed by Democrats as the most important since the Civil War.