The factual centerpiece of the impeachment counts under consideration in the House will no doubt be the administration’s corrupt holdup of Ukraine to advance President Trump’s personal political interests, which the past two weeks have laid bare, witness by devastating witness.

But an additional possible count — based on the White House campaign to undermine and obstruct the impeachment investigation itself — is just as important to the health of our democracy, if not more so. And the case for that count is clear.

The hearings did not plow through the extensive evidence of this obstructive conduct, nor was there any need to, since it has all been undertaken in plain view. But we nevertheless should not lose sight of it. It represents an abuse of power that if allowed to stand would warp and damage the U.S. constitutional structure no less than the grave abuses involving Ukraine.

The offense here is rock-solid on the facts and the law.

The legal theory is straightforward and compelling. Impeachment is the mechanism that the Constitution provides for the most grave abuse of the president’s responsibilities. If the president himself can frustrate that singular remedy, it fundamentally alters the separation of powers and ultimately places the president above effective constitutional control.

It’s also historically well grounded. In 1974, the third count that the House Judiciary Committee returned against President Richard M. Nixon alleged that he had acted in contempt of Congress by willfully disobeying congressional subpoenas that the Judiciary Committee needed to conduct its investigation.

During the hearings last week, Rep. Adam B. Schiff (D-Calif.), the chairman of the House Intelligence Committee, expressly invoked that precedent as he warned the administration, and the State Department in particular, about the unilateral withholding of testimony and documents that could shed light on the case. “I remind the president that Article III of the impeachment articles drafted against President Nixon was his refusal to obey the subpoenas of Congress,” he said.

Trump’s conduct in support of an obstruction count has been flagrant. In blocking a series of subpoenas in the spring, the president announced: “We’re fighting all the subpoenas.” He justified his stonewalling based on an assertion that Congress’s demands were political and “ridiculous.” And true to his word, the president has issued a series of countermands to congressional subpoenas and requests, arbitrarily demanding noncompliance from a series of witnesses, often on the basis of preposterous legal arguments.

It’s worth noting that Nixon’s impeachable conduct was far more tempered than Trump’s has been. Scrambling for his survival, Nixon played a finesse, trying to force a compromise with Congress. The eight subpoenas from Congress called for tapes of 147 conversations and a series of documents. Nixon responded by producing edited transcripts of some of the conversations and a summary of other notes, then went on television to justify his approach to the American people.

By including this conduct in its Watergate impeachment counts, Congress asserted its authority to determine what it needed to pursue its lawful responsibility.

Nixon did not invoke a right to go to court to adjudicate his dispute with Congress. But any such argument from Trump partisans just amounts to a reframing of the same position. Given the pace of even expedited judicial proceedings, forcing Congress to go to court to vindicate its clear legal prerogative is just another way for the president to override Congress’s prerogative.

And while there are some claims of executive privilege in response to a congressional subpoena that might have a fighting chance in the courts (especially the current Supreme Court), the administration’s arguments here are so arbitrary and extreme, and the Congress’s authority to pursue impeachment so integral to the constitutional scheme, that there is no good-faith basis to expect them to prevail.

It is not simply that Trump’s intransigence deprives the committee of necessary information. Taken as a whole, Trump’s contemptuous conduct deprives the country of the critical opportunity to take the full measure of what the president did. There arguably are special constitutional reasons to protect the president himself — an equal branch in his own person — from giving a sworn account of his conduct to Congress. But they do not apply to John Bolton, Mike Pompeo, Mick Mulvaney and others.

House Democrats are reacting the only way they prudently can. Rather than spinning their wheels in fruitless efforts to get the courts to speedily break the impasse, they are adding each successive act of resistance to an expanding potential count of contempt of Congress. “We are not willing to let the White House engage us in a lengthy game of rope-a-dope in the courts, so we press ahead,” Schiff said in October.

The country is now paying attention. The account that has emerged from gripping live testimony over the past two weeks leaves no doubt that senior public officials have even more critical information about what Trump did and when he did it. There is no credible claim of privilege or other legal entitlement to keep this information under wraps. It is not up to the president to decide who complies with their legal obligations and who ignores them.

If the Congress is to retain the power to investigate, impeach and remove the president, the attempted scuttling of the investigation must be taken as an assault on the Constitution — and an impeachable offense in its own right.

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