-- The attack was, quite frankly, planned in plain sight," Democratic Sen. Gary Peters, head of the homeland security panel, told reporters. “There were significant, widespread and unacceptable breakdowns in the intelligence gathering," he said, per the Washington Post. "The failure to adequately assess the threat of violence on that day contributed significantly to the breach of the Capitol."
--In late December 2020, intelligence officers with the Capitol Police picked up messages from pro-Trump supporters saying things like, "Surround every building with a tunnel entrance/exit. They better dig a tunnel all the way to China if they want to escape,” per Politico. Another wrote, "Bring guns. It's now or never."
A bipartisan group of senators released Congress' first report addressing security failures on Jan. 6, faulting the Capitol Police and multiple federal agencies.
--The FBI and Homeland Security similarly picked up such threats, but no one agency seemed to coordinate the warnings. On Jan. 3, a Capitol Police intelligence assessment warned of the possibility of violence, but it wasn't repeated in subsequent reports. The FBI warned the Capitol Police of potential "war" the night before the rally in what the Post describes as a "casually worded" email. But that didn't translate into proper precautions.
--One remedy suggested by the report is to make it easier for the head of the Capitol Police to summon the National Guard quickly, reports the Wall Street Journal. Another is to house the different intelligence-gathering units of the Capitol Police in a centralized location.
A bipartisan Senate report said intelligence and planning failures led to the Capitol breach, and recommended that the Capitol Police chief be empowered to request help from the National Guard in an emergency.