What made the first public hearing of the Donald Trump impeachment inquiry so remarkable was how concisely and effectively it answered the question posed by House Intelligence Committee Chairman Adam Schiff in his opening remarks: “If this is not impeachable conduct, what is?”

Senior US officials painted a picture of an American president who abused his position in order to undermine a domestic political rival, former vice president Joseph Biden. William Taylor, the top US diplomat in Ukraine, recounted a conversation with US Ambassador to the European Union Gordon Sondland in which Sondland said that Trump “cared more about investigations of Biden” than about maintaining responsible relations with Ukraine. Later, when he was asked about evidence that Trump withheld aid to Ukraine as part of his political scheme, Taylor told the committee that “our holding up of security assistance that would go to a country that is fighting aggression from Russia for no good policy reason, no good substantive reason, no good national security reason is wrong.”

Deputy Assistant Secretary of State for European and Eurasian Affairs George Kent was asked, “Is pressuring Ukraine to conduct what I believe you’ve called political investigations a part of US foreign policy to promote the rule of law?” Kent replied, “It is not.”

Then came the essential question: “Is it in the national interests of the United States?”

“In my opinion,” said Kent, “it is not.”

This was devastating testimony, which affirmed the damning evidence of presidential wrongdoing that led to the impeachment inquiry. If Trump was using his office to advance his own political agenda, and if he were doing so in a manner that was in conflict with the national interest, then he was committing precisely the high crimes and misdemeanors that the founders feared when they established the impeachment power.

By any measure, what transpired was bad news for the president—who claimed he wasn’t paying attention to the proceedings but then tweeted madly about them.

So how did the president’s chief defender on the committee, California Republican Devin Nunes, respond to Schiff, and to the mounting evidence against Donald Trump? Not by defending his party’s president as an honorable and responsible leader, but, rather, by ranting about “a three-year-long operation by the Democrats, the corrupt media, and partisan bureaucrats to overturn the results of the 2016 presidential election” and dismissing the mounting evidence against Trump as the product of “a carefully orchestrated media smear campaign.”

Nunes and his fellow Republicans on the Intelligence Committee sought to indict the inquiry rather than to address the issues at hand. Employing a litany of right-wing conspiracy theories and Internet-troll delusions, they offered the American people a powerful insight into determination to obstruct, undermine, and disparage any effort to hold the president to account.

Nunes set the tone with an opening statement that was crudely dismissive of witnesses who have long served presidents of both political parties.

“What we will witness today is a televised theatrical performance staged by the Democrats,” the California Republican began, before speaking directly to the witnesses:

Ambassador Taylor and Mr. Kent—I’d like to welcome you here, and congratulate you for passing the Democrats’ Star Chamber auditions held for the last six weeks in the basement of the Capitol. It seems you agreed, wittingly or unwittingly, to participate in a drama. But the main performance—the Russia hoax—has ended, and you’ve been cast in the low-rent Ukrainian sequel.

Nunes was not alone in signaling that loyalty to Trump would always supersede the facts. Again and again, key Republicans on the committee asked questions and made statements that sounded as if they had been drawn from the president’s Twitter feed. It was a shameless, and shameful, performance. The two key Republican “questioners” on the panel, Ohioan Jim Jordan and Texan John Ratcliffe, asked few questions and spent most of their time portraying Trump as a friend of Ukraine who was simply doing due diligence when he withheld vital aid. At one point in the afternoon, Jordan devoted an extended period of time that had been allotted for engaging with the witnesses to attacking Schiff and claiming that the American people “see through the whole darn sham.”

In fact, polls show the American people are supportive of the inquiry and increasingly favorable to congressional action to impeach and remove the president. Wednesday’s hearing was a critical juncture. Republicans were called upon to mount a meaningful defense of the president or to break with him. They rejected both options and instead provided blank-stare loyalty to a charlatan who does not deserve it.

In so doing, they shamed themselves, and found a way to further diminish the already diminished stature of their party, as a former ally explained in devastating terms.

Noting the overwhelming evidence that the president has been “using the power of the presidency—in its most unchecked area, foreign affairs—to advance his own personal interests as opposed to the country’s,” conservative lawyer George Conway said Wednesday that he was “horrified” and “appalled” with the defenses of Trump mounted by congressional Republicans.

“This is about the country, people doing the right thing by the country and not by their party. And this is about telling the truth about what really happened and not about party loyalty,” the husband of White House counselor Kellyanne Conway declared on MSNBC. “This is about putting the country, the law, truth above partisanship.”

Conway is right. He speaks as a conservative who has worked with top Republicans and often aligned with them on constitutional matters. Unfortunately, his remains a lonely voice. And during the first of many public impeachment hearings, Nunes and his wrecking crew sent an unsettling signal regarding their disregard for the truth and for the Constitution.

House Republicans are refusing to fulfill the oath they swore to “support and defend the Constitution of the United States against all enemies, foreign and domestic,” to “bear true faith and allegiance to the same,” and to “well and faithfully discharge the duties of the office.”

Nunes and his compatriots are doing precisely what Trump did: placing a political agenda ahead of the national interest. It is an awful thing to witness. They are making themselves and their party into an American abomination that is every bit as appalling and horrifying as George Conway suggests.