An angry moband onto the floor of the United States Senate – a scene as once unthinkable as airplanes crashing into buildings.
"They could have blown the building up," said Sen. Lindsey Graham. "They could have killed us all. They could have destroyed the government. We dodged a major bullet yesterday."
The barriers erected and manned by the Capitol Police were little more than speed bumps to the angry mob.
"They had these pathetic little barricades up beforehand, and what they should have done is had much more robust capabilities well in advance of the sixth of January," said former Homeland Security Secretary Michael Chertoff.
He told CBS News national security correspondent David Martin that the Capitol Police bear primary responsibility. "This strikes me as having been a real dereliction by the Capitol Police," he said.
But simple dereliction doesn't explain this statement by D.C. Police Chief Robert Contee: "There was no intelligence that suggested there would be a breach of the U.S. Capitol."
In fact, social media was full of "Storm the Capitol" rhetoric, including a tweet from President Trump, predicting it "will be wild."
And then, there was the rally outside the White House. "Let's have trial by combat," Giuliani pronounced.
Chertoff said, "If you read the newspaper, you knew that there was a serious possibility of a threat against the Capitol. 'Let's go wild.' 'Bring your guns.' It doesn't take a rocket scientist to figure out that that suggests a serious threat to the integrity of the Capitol."
This was not a failure to connect the dots but a failure to believe the dots.
"Whether they underestimated the threat or believed – because they were Trump supporters – they weren't going to be a problem, that was a very serious error, and can never be allowed to be repeated," Chertoff said.
Martin asked, "Was this cultural bias? If it's Black Lives Matter there's a real threat of violence here, but if it's just almost all White Trump supporters, no problem?"
"Certainly, that's a legitimate question to ask," Chertoff replied. "They need to ask questions about whether there was conscious or unconscious bias, or even some, you know, political spin for some of the people in the Capitol Police."
Democratic Congressman James Clyburn offered a more sinister explanation: "Somebody on the inside of those buildings [was] complicit in this."
The need for answers is urgent. There are already social media calls for. The president is vowing, 'We will not be SILENCED!" And one of his supporters warned, "Many of us will return on January 19 carrying our weapons."
"Buckle up," Chertoff said. "I'm afraid we're going to see some very scary activity over the next weeks and months."
Story produced by Mary Walsh & Mary Raffalli. Editor: Greg Hotsenpiller.