This small space in the basement of the Capitol with steel bars is sometimes referred to as the Capitol jail. But Congress has no jail. (J. Scott Applewhite)

Congress can arrest people who don’t obey its orders to come talk — like Attorney General William P. Barr jokingly dared House Speaker Nancy Pelosi (D-Calif.) to do on Wednesday. (“Madam Speaker, did you bring your handcuffs?” he asked her.) But jailing them is a whole different problem.

Since the Civil War era, congressional historians can recall half a dozen notable times when Congress jailed people. Actually, “contained” people is a better word. Because every time Congress has arrested someone, it has had to improvise how to hold them, and the jailing itself has often backfired in terms of public sentiment and Congress’s overall goal of getting information.

So even if Congress wanted to jail Trump administration officials who won’t comply with subpoenas — as some House Democrats are openly considering, given that they don’t expect the Justice Department under Trump to jail its own attorney general — it’s an open question how effective that would be.

"There are some logistical issues,” said Donald Ritchie, a former Senate historian. “It's not worked in the past when they've tried it."

Some of these past “jailed” offenders have sued Congress; others have milked it for all it was worth. In 1848, jailed journalist John Nugent, who refused to share the source who gave him a copy of a leaked treaty, had his salary doubled by his paper and datelined his stories, “Custody of the Sergeant at Arms.”

One wealthy abolitionist jailed by Congress in 1860 for not cooperating with an investigation bought lavish furniture for his quarters. “He spent his incarceration organizing anti-slavery rallies,” according to the U.S. Senate Historical Office, “writing newspaper articles, and receiving dozens of sympathetic visitors."

A decade later, a wealthy real estate speculator who was jailed by the House of Representatives for refusing to answer questions about his bank’s real estate practices was held in an annex behind the Capitol, where he racked up the equivalent of $12,000 in meal costs on Congress’s dime within a few days — including oysters, wine, whiskey, broiled chickens and strawberries. Hallet Kilbourn also aroused public sentiment while locked up. (“The press swooned over his story,” reported the historian’s office in the House of Representatives.)

The logistical problem for lawmakers in 2019 to get around if they wanted to jail, say, Attorney General William P. Barr, is one that has hindered Congress from the beginning: It doesn’t have a jail.

Although many people think there is one. If you’ve ever taken a tour of the Capitol and stood under the rotunda, off to the side are some stairs leading down to a lonely room covered by iron bars. It looks pretty jail-y to anyone who peeks down — which is why some tour guides even mistakenly say it’s an old congressional jail.

“Anybody who walks past it would think, what else could that be used for,” said Katherine Scott, a historian at the U.S. Senate Historical Office. It was built to be a tomb for George Washington, whose family decided to keep him with his wife. In the past, it has been used for storage. Today it holds the Lincoln Catafalque, the pedestal for caskets used during state funerals.

The D.C. local jail has held a couple of people in contempt of Congress before. A couple also have been held for a day or two in empty committee rooms.

More often than not, though, jailing people for contempt of Congress has not really been the punishment that Congress might want it to be. A former Hoover administration official was held at the cushy Willard Hotel for a night after also spending a night at the home of the sergeant at arms. (He did eventually serve time in jail, though with special treatment.) That 19th-century jailed journalist, Nugent, was held for a month in a Senate committee room. He went home every night with the sergeant at arms, slept in a clean bed and got fed. “Obviously, he wasn’t suffering,” Scott said.

Congress has sent people who were voted to be in contempt of Congress straight from the floor of the House or Senate to a local jail, The Washington Post reported in 1934. But powerful witnesses whom Congress wanted to jail — such as an oil magnate or banker — resisted at first, which threatened to weaken Congress’s inherent power to protect its investigative abilities.

The most recent time Congress flexed its jailing muscles actually ended up weakening it. In 1916, Congress arrested the U.S. attorney for the Southern District of New York after a contempt charge that looked very much like a case of political retaliation. (The attorney, H. Snowden Marshall, had headed an investigation that led to the indictment of a congressman.) When Marshall was arrested, he appealed his case all the way to the Supreme Court and won. The case, Marshall v. Gordon, ended up narrowing Congress’s arresting power to only instances in which the witness is preventing or obstructing Congress’s job.

Some House lawmakers today argue that Trump officials are doing exactly that, blocking Congress’s inherent oversight duties. But if they wanted to take the drastic step of jailing those officials, history doesn’t provide much guidance on how.