President Trump's latest effort to obstruct the impeachment inquiry into himself came on Tuesday, with the announcement that he told U.S. ambassador to the European Union Gordon Sondland not to show up to his scheduled deposition with House investigators. The subject was to be his recently-revealed text messages with other diplomats discussing Trump's effort to coerce Ukraine into publicly investigating the Biden family. Sondland's lawyer said he had no choice but to obey Trump, but that's a lie — Sondland could resign and ignore Trump's order if he really wanted to. In response, House Democrats say they'll issue a subpoena for Sondland's testimony along with the emails and texts from his personal device that the State Department is reportedly withholding.

If he doesn't comply, the House should be prepared to clap this man in irons and forcibly drag him to the Capitol to testify. Trump cannot be allowed to prevent testimony into his criminal abuses of power.

For one thing, Trump's explicit argument is that the Democratic-controlled House should not be allowed to investigate him at all. On Twitter Tuesday morning, he wrote that Sondland "would be testifying before a totally compromised kangaroo court, where Republican's [sic] rights have been taken away[.]" Just as when Trump's lawyers recently argued in federal court that he should be immune from criminal investigations (dismissed by a federal judge who said his argument was "repugnant to the nation's governmental structure and constitutional values"), Trump does not believe he should be subject to any oversight or laws of any kind.

This move also puts paid to any claptrap about this being anything other than Trump trying to use his power to cover up his misdeeds. He will not allow anyone to testify if he can help it, and he's not going to respect any constitutional niceties in the process.

For another, alternative methods to force Sondland to testify are slow or under Trump's control. The House can cite him for contempt and then turn that over to the local U.S. Attorney for prosecution — but she was appointed by Trump and thus cannot be trusted. Alternatively, the House could file a lawsuit and try to get a judge to back them up — but Trump has heavily stacked the judiciary with loyal partisans, and such lawsuits take forever.

Which is why House Democrats would have no choice but to lock up Sondland on the basis of "inherent contempt." As this Congressional Research Service report explains, this is a long-unused power whereby Congress directly votes to hold someone in contempt, arrests them, and punishes them (usually by imprisonment). The arresting officer is one of the two sergeant-at-arms, who manage security in the two wings of the Capitol (along with some deputies), and perform some ceremonial duties. In the 19th century, both the House and the Senate routinely arrested and imprisoned people for stuff like attempted bribery of members of Congress, refusing to testify before various committees, assaulting a representative, and so on.

The Supreme Court has repeatedly upheld the inherent contempt power. In McGrain v. Daugherty in 1927, it ruled that this was a necessary part of Congress' governing authorities: "Each house of Congress has power, through its own process, to compel a private individual to appear before it or one of its committees and give testimony needed to enable it efficiently to exercise a legislative function belonging to it under the Constitution."

Subsequent rulings narrowed the power somewhat, holding that a contempt citation has to be "necessary to preserve and carry out the legislative authority" of Congress. However, an impeachment inquiry is unquestionably within the purview of Congress, and refusing to testify because the opposite party controls the chamber in question is a baldly ridiculous excuse. And it would be procedurally simple — just hold Sondland until he spills the beans.

So the House would be on firm legal footing. But the political aspect here is just as important. The whole Trump administration is flailing around in chaos, and Trump himself is in even more of a frantic rage than usual, doubling and tripling down. Men like him and Sondland (a major GOP donor with no diplomatic experience) have grown up cosseted in the warm blanket of America's total impunity for elites. They've never experienced a real consequence in their lives. Slapping him in cuffs would make it clear that there are some real stakes here, and set an important lesson for the dozens of other Trump stooges who will certainly need to be subpoenaed. Meanwhile, it will continue to drive Trump to greater fits of manic desperation (in addition to, you know, getting some testimony in an area of vital importance).

I judge the likelihood that Speaker of the House Nancy Pelosi or any of the rest of the House leadership will suddenly grow a spine as slim — though chairman of the House Intelligence Committee Rep. Adam Schiff hinted to The Washington Post's Greg Sargent that all options are on the table. Nevertheless, it's clear that Trump is attempting to effectively annul Congress' subpoena power. If Democrats don't want it to disappear, they better fight to protect it.

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