There’s still much we don’t know about what happened during the months in which Donald Trump and his administration were leaning on Ukraine to conduct “investigations” that could yield domestic political dividends for the president. Here’s what we do know:

The rough transcript of the call between the American president and his Ukrainian counterpart confirms the whistleblower’s central complaint: that Trump had explicitly linked his desire for a “favor” to Ukraine’s interest in American arms to combat the Russian forces that occupy Donbass. That “favor” involved the president’s wish to see “corruption” investigated, but the only corruption the president mentioned involved allegations against Joe Biden’s son and the whereabouts of a “server” that the president seems to believe could contain Hillary Clinton’s missing emails from her tenure at the State Department.

Chief of Staff Mick Mulvaney offered an unconvincing walk back, but the White House has since confirmed that the administration did, indeed, couple the disbursement of inexplicably delayed military aid—congressionally authorized non-lethal assistance distributed to Ukraine at regular intervals for years—with the adminstration’s wanting Kyiv to conduct “investigations” on its behalf. Mulvaney specifically noted that the whereabouts of the mysterious server was high on the administration’s list of interests.

And now, on account the testimony of Ambassador William Taylor, Trump’s current chargé d’affaires for Ukraine, we have reason to believe this enterprise was not one of Trump’s flights of fancy but a concerted, administration-wide effort. Taylor confirmed that the interest in the “server” was a proxy for Trump’s desire to establish “Ukrainian interference in the 2016 U.S. election,” which would muddle the case against Russia over its extensively confirmed culpability in a campaign to hack DNC servers and change the course of American political events. He quoted America’s European Union Ambassador Gordon Sondland saying that Trump wanted to put the Ukrainian president “in a box,” forcing him to publicly confirm the existence of investigations into the Bidens and the server. “Ambassador Sondland said, ‘everything’ was dependent on such an announcement, including security assistance,” Taylor testified. “The irregular policy channel was running contrary to the goals of longstanding U.S. policy.”

So far, that’s the most damning aspect of this whole affair. The president’s defenders appear to believe that the White House’s interest in renewed investigations into Hillary Clinton’s server is less politically explosive than its poorly disguised effort to taint Joe Biden and his family with the patina of criminality. Why else would Mulvaney have confessed to it? And they’re right: Superficially, a retrospective look into the events of 2016 is less politically explosive than an attempt to leverage the presidency in the effort to damage one of Trump’s prospective opponents in 2020. Perhaps they also believe that their interest in the 2016 campaign can be tied to the Justice Department’s perfectly valid inquiry into the origins of the Justice Department’s 2016 probe of Trump campaign associates. But upon closer inspection, the president’s attempt to derail a critical aspect of American foreign policy while sidelining Congress’s expressed intent is equally, if not more, negligent. That’s due in no small part to the fact that the president’s interest in the server is based on a crackpot conspiracy theory.

To get to the bottom of Trump’s investment in the alleged server in Ukraine is to spelunk the fringiest of lunatic rabbit holes. The theory goes something like this: CrowdStrike, a cybersecurity firm that helped the FBI investigate the 2016 hack into DNC email accounts, is owned by a wealthy Ukrainian (it’s not; the company’s co-founder is a Russian-born U.S. citizen). The digital imaging of the DNC’s hard drives deliberately hid evidence that Ukraine, not Russia, was the party behind the infiltration of Democratic communications networks. To hide its nefarious deed, the firm absconded with the DNC’s hardware, spiriting it off to Eastern Europe, where it would entomb all the nastiest secrets of the president’s enemies.

To believe this theory, you must discount all the available evidence, including the findings and indictments handed down by Robert Mueller’s investigation, which confirmed in exhaustive detail how the Russian-led interference operation was conducted. But that’s precisely what Trump believes. “There was a server, the DNC server, that had never went to the FBI—the FBI didn’t take it,” the American president told Fox News Channel’s Sean Hannity this weekend. “It was taken by somebody. I guess it’s CrowdStrike. That’s what I have heard.” The president told reporters in the Oval Office that he continues to press the FBI to discover the whereabouts of this McGuffin. “How come the FBI never got the server from the DNC?” he asked. “I want to see the server.”

Leaving to one side the president’s efforts to compel his foreign counterparts to put Joe Biden in a disadvantageous position, the allegations involving Trump’s interest in this mystifying conspiracy theory are as, if not more, troubling. In service to this mania, the president derailed a critical aspect of U.S. grand strategy. It is in America’s permanent national interest to contain armed conflicts between great powers on the European continent and to constrain Russia’s revisionist ambitions. The president certainly attempted to use access to the White House as a pry bar in furtherance of this conspiracy theory. He likely, according to the sworn testimony of his ambassador, dangled life-saving military assistance to Ukraine in that effort. This is no longer a petty, domestic political scandal but an assault on vital U.S. strategic interests abroad.

We still do not know for certain whether American military aid was held in abeyance to force the Ukrainian president into a “box,” though Taylor’s testimony goes some way in confirming that. We do not know how Ukraine’s new president responded to this pressure or if his behavior changed as a result. And we do not know if the Trump administration established any moiety between its interest in seeing the Biden family investigated and its desire to introduce some ambiguity into the idea that Russia intervened in 2016 on Trump’s behalf. But even setting all that aside, the all but confirmed revelation that the president subordinated essential American interests in deference to a crank theory that bubbled up from online message boards is disturbing enough. What’s more, everyone, including Trump’s Republican allies in Congress, knows it.