Donald Trump holds a chart of military hardware sales as he welcomes Saudi Arabia's Crown Prince Mohammed bin Salman in the Oval Office in May 2018.Jonathan Ernst / Reuters

As President Donald Trump’s critics focus anew on whether he obstructed justice to thwart Special Counsel Robert Mueller’s investigation, a more flagrant abuse of presidential power is unfolding in plain sight.

For weeks, Trump has continued America’s involvement in the war in Yemen, siding with Saudi Arabia against Congress, the body that the Constitution vests with the power to declare war. The House last month approved a resolution, 247 to 175, directing the president to withdraw the U.S. from the war on Yemen. A bipartisan Senate majority had already approved the same resolution. And the American public has no appetite for a long war in Yemen.

On its own, waging war after an official call from Congress to stop doing so ought to be regarded as a violation of the Constitution that warrants impeachment.

But there’s even more to the Trump administration’s “Saudi Arabia First” foreign policy: Citing a provision in the Arms Export Control Act that allows the president to bypass the legislative approval process in an emergency, the administration is circumventing a block on arms sales to the Saudis.

“We have the constitutional duty to declare war and the responsibility to oversee arm sales that contravene our national security interests,” Democratic Senator Chris Murphy has complained. “If we don’t stand up to this abuse of authority, we will permanently box ourselves out of deciding who we should sell weapons to.”

Congress ought to eliminate the emergency provision. But the provision’s existence does not justify its invocation when there is no actual emergency. Secretary of State Mike Pompeo says the weapons are needed to deter Iran, but that hardly amounts to an immediate crisis.

Daniel Larison notes:

The weapons that the U.S. sells to the Saudis and the UAE won’t be used to defend against a supposed Iranian threat, and they won’t be used for deterrence. We know very well that the Saudi and Emirati governments will use the weapons they obtain from the U.S. to continue waging an atrocious war against Yemen, and those weapons will very likely end up being used to kill civilians as so many other U.S.-made weapons have been. Trump is helping to fuel Saudi coalition aggression against a poor country that they have been wrecking and starving for more than four years. This will not avert a war with Iran, but it will help to keep the war on Yemen going.

Put succinctly, the Trump administration unlawfully defied Congress to extend American participation in a war in Yemen, and now it is defying America’s elected representatives again to funnel more weapons to that war’s ringleader.

It’s the legislature’s move.

Perhaps a lawsuit of the sort urged by some legal scholars who believe votes against wars cannot be constitutionally vetoed by the president would prove effective.

“I’m confident these new arms sales provides new momentum for pursuing legal action and legislation that would end U.S. involvement in the war,” Democratic Representative Ro Khanna stated on Twitter. “The lawsuit is important to uphold Congress’ constitutional War Powers & challenge President Trump’s veto of our Yemen WPR.”

But there is a more direct remedy available to Congress. So long as some of its members are invoking alleged obstruction of justice to justify impeachment proceedings, they ought to invoke abuse of the war power, too. The prospect of being removed from office is far more likely than even a successful lawsuit to deter this president and his successors from usurping the legislature’s authority.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.