Congress may have the benefit of 1,600 police officers and classified intelligence, but its accessibility has worried the Capitol Police for years.

As the house of the people, it is open to the world: Visitors can walk through a metal detector and be in any House or Senate office building, tourists can wander right up to the Capitol’s walls and any citizen can walk into the Capitol if they have an appointment inside.

This setup has contributed to occasional embarrassments over the years.

In 2006, for example, a gun-toting Carlos Greene crashed an SUV on the East Front Plaza and managed to run into the Capitol, with the police in pursuit. An employee at the House Flag Office finally stopped Greene and held him in a bear hug until police arrived.

The Capitol Visitor Center is supposed to make such breaches more difficult. As of Tuesday, if everything goes according to plan, visitors to the Capitol will no longer be able to enter through any door — only through the main CVC entrance.

“It’s to get all visitors to go to one location,” Capitol Police Chief Phillip Morse said. “It helps us, with a little more ease, see people who are approaching the building.”

Police and CVC officials have stressed the benefits of screening visitors 100 yards from the Capitol. This aspect was especially appealing in 1998, after Russell Weston was able to gain entrance to the Capitol — and go on a shooting spree — by killing an officer at the Capitol’s entrance.

But Morse also noted a slew of security enhancements.

At the CVC, visitors will go through one of eight magnetometers, while their bags will be swabbed to check for explosive material. If additional searches are necessary, police will escort them to a separate room — much like at an airport.

There are also ballistic podiums and the latest in X-ray technology. And when visitors are in the CVC, they’ll constantly be on camera.

In comparison, visitors who want tours now stand underneath a tent on the Capitol’s south side. Others can simply walk to the North or South entrance, tell an officer of an approaching appointment and register as a guest at a desk inside the Capitol.

“I definitely think it’s an improvement,” Senate Sergeant-at-Arms Terrance Gainer said. “I know there been some consternation over the delay and cost, but I know from a security perspective we added a lot of different features as a result of technology being developed over those years.”

Still, the CVC isn’t a cure-all for Capitol security, Gainer acknowledges. Visitors can still walk right up to the Capitol without going through any security screening. In fact, with the CVC open, they’ll be able to walk on the Capitol’s East Front for the first time in years.

“It’s not an ideal situation by any stretch,” Gainer said. “From a security perspective, I still wish we could somehow design a very tasteful fence that stretches from Constitution to Independence and from [First Street Southwest] to [First Street Southeast], where people could still come in at all times of the day.”

But, he added, those security ideals may not mesh with the ideal of keeping Congress open and accessible.

“I think it’s a risk that the leadership is willing to take and Members are willing to take,” he said.

The Capitol Police will also have to guard a larger area. The CVC is 580,000 square feet, with a footprint that is larger than the Capitol itself. In the past few months, the Capitol Police department has pushed through more recruits to beef up its forces and plans to add more next year.

“It’s obviously something additional to manage,” Morse said. “But that’s easily done.”