As Justice and Defense department officials planned for the turmoil that was coming Wednesday, they knew that pro-Trump protesters — including some violent extremists — might try to storm the U.S. Capitol as lawmakers prepared to certify the election of Joe Biden. So why weren’t they better prepared for the catastrophic assault that took place?

That’s the riddle at the center of Wednesday’s spasm of violent anarchy: Officials saw the mob coming but weren’t ready or able to stop it — and they allowed hundreds to invade the Capitol, threaten lawmakers and, for a time, foment a coup inside the most precious symbol of U.S. democracy.

The answer is surprisingly simple, if unsatisfying: Senior officials believed that the force they were assembling of 6,000 to 8,000 police and law enforcement officers — drawn from the D.C. police, the Capitol Police, the FBI and various federal agencies — would be sufficient to contain the protests. For backup, the D.C. National Guard would be available, but those troops are useful for assisting with crowd control; they’re not a SWAT team.

Trump supporters overtook Capitol Police officers to enter the building as lawmakers attempted to count the electoral college votes on Jan. 6. (The Washington Post)

To deal with the expected march from the Ellipse to the Capitol, the Capitol Police planned to expand the normal perimeter around the building and arrest anyone who tried to breach it. As it turned out, they were utterly unprepared for the assault that came. When asked why the Capitol Police hadn’t taken more aggressive action or called in backup more quickly, one senior official responded only: “That’s a good question.”

Defense and Justice officials crafted their plans with one primary but unstated goal: They wanted to rely on law enforcement and avoid any use of active-duty military. In that, at least, they appear to have been successful. But in their effort to avoid giving President Trump a pretext for invoking the Insurrection Act, they allowed what looked to all the world like an insurrection.

The command posts for Wednesday’s operations were the Justice Department and the mayor’s office, not the Pentagon. Acting Defense Secretary Christopher C. Miller and Gen. Mark A. Milley, chairman of the Joint Chiefs of Staff, monitored the situation. But the Pentagon’s representative at the Justice Department was Army Secretary Ryan McCarthy, who was responsible for overseeing the National Guard.

The hard fight — clearing the inside of the Capitol of the insurgents who had invaded — was led by SWAT teams from the FBI; the Bureau of Alcohol, Tobacco and Firearms and Explosives; and other agencies, one official said. The Pentagon brass were insistent that the regular-duty military shouldn’t be used in quelling a civilian protest inside the United States — even one as violent as Wednesday’s.

These shattering events may turn out to have some benefits in quelling the pro-Trump insurgency that had been gaining strength. The “protesters” were seen for what they were: a lawless mob bent on breaking windows, trashing the Capitol and threatening the integrity of the government. The pictures of smug, would-be freedom fighters luxuriating in House Speaker Nancy Pelosi’s (D-Calif.) office and in the Senate chamber disgusted even hard-core Trump supporters.

The law enforcement approach may have looked timid and allowed the horrifying invasion of the Capitol. But the low-key response avoided any Tiananmen Square scenes of armed military or paramilitary forces attacking citizens. The mob must have been hoping for such a propaganda moment. At this writing, they don’t have it. Instead, they have public revulsion.

Although the insurgents managed to delay the final certification of Joe Biden’s electoral college victory, they did so at a cost of shattering their movement to challenge the election result. Even the most craven Trump supporters, like Sen. Ted Cruz (R-Tex.), seemed embarrassed that their challenge to Biden had produced this alarming spectacle.

Senate Majority Leader Mitch McConnell (R-Ky.) was speaking for GOP self-preservation when he rejected the attempt to derail Biden’s election Wednesday afternoon, shortly before the invasion began. How fitting that he will soon become minority leader, as triumphs in the Georgia Senate runoffs give the Democrats control of the Senate. The public repudiation of Trump’s reckless, seditious actions has been growing, month by month, and McConnell knows it.

One lesson from this debacle is that right-wing militia groups pose a serious threat to the country’s stability. They surely harmed their cause with most Americans, but they probably boosted their image among the millions of self-styled patriots who share their conspiracy theories and dreams of a new 1776 revolution. The mob at the Capitol is part of a global movement of white extremists; it recruits and operates through social media; it’s armed and dangerous; it seeks the overthrow of our constitutional government.

Planning a strategy to contain this movement without giving it the martyrdoms it seeks should be a top priority for the Biden administration.

Read more: