The riot and ensuing attack on the U.S. Capitol on Jan. 6, 2021, was fueled in part by homegrown violent extremists adhering to racist and anti-government ideologies. Dr. Erroll Southers spoke with Foreign Policy editor James Palmer to explain the terrorist threat, the law enforcement failures and the security priorities going forward.

Read an interview excerpt below and find the entire interview in Foreign Policy.

Foreign Policy: What went wrong on Jan. 6?

Erroll Southers: Where do I begin? Obviously, they did not heed the open-source information by individuals and groups about their planned intentions for Jan. 6, accompanied by the statements from the executive office and the constant drumbeat since Nov. 3 to suggest that the election was unfair or rigged—and this could be corrected despite 60 lawsuits, 59 of which failed, a rejection from the Supreme Court, and all of the Electoral College votes being in place. The first thing that went wrong is that the agencies involved, despite all of that information, especially the [information about] violence, thought they were going to have a peaceful assembly, and that it would end peacefully. It went totally off the rails when some of the speeches were made in the speeches that morning.

I honestly believe a 9/11 Commission should be undertaken to review this incident. There was a full independent review of the Charlottesville incident—an excellent review by an independent group—and this was like Charlottesville on steroids. The review has to cover the multiple intelligence failures. Months ahead of this, [the Department of Homeland Security]’s threat assessment unit was gutted by the executive branch. The agencies didn’t work together anticipating this kind of activity. Requests to send in the National Guard were ignored—and so it went from bad to worse to terrible. The Charlottesville review, although the department didn’t like it, was very fair.

Leading up to this, we knew there would be violence that day. In fact, I predicted violence at every state capitol, and there was violence at many of them. This was not a secret. You didn’t have to have a security clearance to know what was going to happen.

Read the full interview in Foreign Policy.