The U.S. Capitol Police force was caught unprepared by a mob of pro-Trump extremists today, in a failure to protect the seat of American democracy unparalleled in modern times.

Rioters, bearing Trump garb, breached the barricades set up by an under-staffed police force and swarmed the Capitol, disrupting the certification of President-Elect Joe Biden’s election and forcing the evacuation of Vice President Mike Pence and other lawmakers.

Calm was eventually restored after the National Guard was called out and more than a dozen people were arrested. At least one person was killed inside the Capitol. Washington Mayor Muriel Bowser ordered a 6 p.m. curfew.

With Washington routinely scene to large protests, the Capitol Police “should have been preparing for this for years,” said Daniel Schuman, policy director at Demand Progress, an advocacy group. “So the question is, ‘Why did they fail so terribly?”’

The failure is all the more remarkable because local authorities were on high alert over the arrival of thousands of Trump supporters as they gathered to hear the defeated president — who had invited the protests — bemoan the unfounded allegations of election fraud.

“They knew this group was coming, they knew it was going to be enormous but they didn’t do any preparation to control the crowd such as fencing, barricades, and cement structures to prevent traffic and people flow,” said Timothy Dimoff, a former SWAT force member who runs a security consulting company.

A spokesperson for the Capitol Police did not respond to a request for comment on criticism surrounding preparations for the day.

The mayhem shortly after midday signaled the start of an extraordinary episode that saw District of Columbia police, officers from neighboring Virginia and Maryland, and the D.C. National Guard join to recover control of the U.S. Capitol from the president’s supporters.

“It was clear that the crowd was intent on causing harm to our officers by deploying chemical irritants on police, to force entry into the United States Capitol building,” D.C. Metropolitan Police Chief Robert Contee III said in a news conference.

“What we witnessed was unlawful and riotous behavior,” Contee said.

Protesters flooded the building, with some of them entering the House chamber and sitting at the dias while one man apparently entered House Speaker Nancy Pelosi’s office. Video on social media showed one policeman desperately trying to hold back more than a dozen protesters as they ran up the stairs inside the building.

By nightfall, police were using flash-bang devices to disperse crowds around the building. The U.S. Capitol was declared secure this evening, about four hours after the mob stormed the building. Congressional leaders said debate on certification of the Electoral College would resume.

On the floor of the Senate this evening, Democratic leader Chuck Schumer called the events “a stain on our country not so easily washed away.”

There were at least 13 arrests and five weapons seized, including long guns, Contee said. None of those arrested was from the District of Columbia, he said.

A spokesman for the District of Columbia police, Alaina Gertz, said a woman had been fatally shot at the Capitol, providing no further details. Earlier, Police were seen providing aid to a bloodied woman lying on the floor inside the building. It not immediately clear if that was the woman who was shot.

Around 3 p.m., the District of Columbia’s National Guard called out its entire roster of about 1,100 people to help restore control, Army Secretary Ryan McCarthy said. The D.C. National Guard is unique among such forces because it reports only to the president.

Unlike with previous protests such as Black Lives Matters, this one had a powerful supporter. While President Donald Trump told violent protesters who stormed the U.S. Capitol to “go home now,” he earlier egged them on to help stop the transfer of power from taking place.

“President Trump doesn’t say go out and attack the capital but he is encouraging people to believe that the election was stolen,” said Jessica Stern, a professor on terrorism and white supremacy at Boston University. “The pressure has built up to the point they felt inspired to act now.”

The Capitol Police force describes its mission as protecting “Congress, Members of Congress, employees, visitors, and Congressional buildings and grounds from crime, disruption, and terrorism.”

The department has an authorized sworn strength of more than 2,000 and an annual budget of $460 million. In addition it has over 350 civilian personnel who provide operational and administrative support.

Representative Steve Scalise, the Republican whip from Louisiana, applauded their efforts.

“You saw the Capitol Police do what they do every day. They risked their lives for us,” Scalise said in a statement after the Capitol had been secured. “They keep the Capitol safe — those heroes that we love.”

But Democratic Representative Tim Ryan, chairman of the panel responsible for funding the Capitol Police, told reporters that some law enforcement officials should lose their jobs.

“It’s pretty clear that there’s going to be a number of people who are going to be without employment very, very soon,” Ryan, of Ohio, said in a digital press conference today. He criticized “the lack of professional planning and dealing with what we knew was going to occur.”

Ryan, chairman of the House Appropriations Legislative Branch subcommittee, said he talked to House Sergeant at Arms Paul Irving and Capitol Police officials about the long-planned protest as recently as Tuesday, and that it was clear protesters were not supposed to be “anywhere near the Capitol,” instead restricted to a nearby area to “protest and express your view,” Ryan said.

Republicans Recoil From Trump After Mob Violence Proves Too Much

People who went up the Capitol steps should have been immediately arrested, and there should have been reinforcements ready to help, Ryan said.

“There were clearly enormous strategic and planning failures by the Capitol Police, by the sergeant at arms, and anybody else who was a part of coordinating this effort here,” Ryan said.

The U.S. Capitol Historical Society, a congressionally chartered educational group, posted a message on its website today under the heading, “Democracy is Stronger Than Terror.”

The then-unfinished building first housed Congress in 1800 and was famously overrun and burned by British troops in 1814 as part of the War of 1812.

“The United States Capitol Historical Society is shocked and heartbroken by today’s violent disregard for American values and our Constitution,” the group said. “The U.S. Capitol is more than a building – it is the embodiment of American democracy and our way of life.”