Americans who have been wondering why President Trump has taken the extraordinary step of trying to block every document from being released to Congress in his impeachment inquiry need wonder no longer. The new documents released Tuesday evening by the House Intelligence Committee were devastating to Trump’s continuing — if shifting — defense of his Ukraine extortion scandal, just days before his impeachment trial is likely to begin in the Senate. These new documents demolish at least three key defenses to which Trump and his allies have been clinging: that he was really fighting corruption when he pressured Ukraine on matters related to the Biden family; that Hunter Biden should be called as a witness at the Senate impeachment trial; and that there’s no need for a real, honest-to-goodness trial in the Senate.

The most basic principles of constitutional law require relevant information, including documents and executive branch witnesses, to be turned over to Congress in an impeachment proceeding. Particularly because sitting presidents cannot be indicted, impeachment is the only immediate remedy we the people have against a lawless president. For that remedy to have any teeth, relevant information has to be provided. That’s why President James Polk said that, during impeachment, Congress could “penetrate into the most secret recesses of the Executive Departments … command the attendance of any and every agent of the Government, and compel them to produce all papers, public or private, official or unofficial.” No president, not even Richard Nixon, thought he could just say “no” to impeachment. That’s why the House added Article II to Trump’s impeachment: “Obstruction of Congress.” It was a response to an unprecedented attempt by a president to hide the truth.

The documents released Tuesday show what Trump has been so afraid of. For starters, they prove that his already-eyebrow-raising claim to have been fighting corruption in Ukraine was bogus. Notes taken by Lev Parnas — who is an associate of Trump’s personal lawyer Rudolph W. Giuliani and is now facing federal criminal charges — show what his and Giuliani’s mission was when they got in touch with Ukrainian President Volodymyr Zelensky: “get Zalensky to Announce that the Biden case will Be Investigated.” Look hard at the real goal here: not to prompt an investigation of Hunter Biden, but to score an announcement of a Biden investigation. Pursuing an announcement, rather than an investigation, makes sense only if Trump’s objective was to dirty the reputation of Joe Biden, a leading political rival.

Both of us served in high-ranking Justice Department positions; we’ve never heard of an investigation that is kept from the Justice Department, given to a private lawyer and then publicly announced — investigations work best when done in secret. If Trump, as he has long claimed, was truly interested in pursuing anti-corruption efforts in the bizarrely specific form of a single investigation of a single American citizen, then he would have wanted an actual investigation. Instead, he was fixated on the public announcement of one — which, if anything, would have harmed the investigation by tipping off its subject. The public announcement would have helped only one thing: Trump’s personal political prospects.

And if Trump wasn’t really pursuing corruption in Ukraine, then his demand that Hunter Biden be called as a witness at the upcoming Senate impeachment trial also crumbles. This effort by Trump and his allies to shift attention away from Trump and toward the Bidens makes no sense on its own terms — after all, the president is the one being accused of impeachable offenses, not Joe or Hunter Biden. But the effort defies logic entirely, because Parnas’s notes make clear that his and Giuliani’s marching orders from Trump were to provoke a Ukrainian announcement of a Biden investigation, rather than an investigation itself. What could Hunter Biden possibly tell the Senate about that?

Trump’s push had nothing to do with what Hunter Biden did or didn’t do, and everything to do with whether Trump could extort and bully the Ukrainian leadership into casting aspersions on Biden regardless of what he did or didn’t do. That leaves Biden with nothing of relevance to say at a Senate impeachment trial — the final word on Trump’s preposterous effort to refocus scrutiny on the Biden family. That was, of course, the very push that got Trump into this mess in the first place, so to allow him to succeed now through the mechanism of impeachment would be irony bordering on tragedy.

But that’s not to say there’s nothing to learn at a genuine Senate impeachment trial — which, as the word “trial” suggests, features actual evidence and witnesses. That’s the third point emerging from the documents released Tuesday night. One of those documents shows how important it might be to have such witnesses testify before the Senate. The document is a letter from Giuliani to Zelensky when he was Ukraine’s president-elect. It begins: “I am private counsel to President Donald J. Trump. Just to be precise, I represent him as a private citizen, not as President of the United States.” The letter then requested a meeting with Zelensky. This letter is a devastating indication of what has been clear to many all along: that Trump’s pursuit of an announcement that Ukraine was looking into Biden was an abuse of his public office for personal gain. That’s what this letter sure seems to be saying. And it makes clear that what was afoot had nothing to do with law enforcement or Biden’s possible corruption — it wasn’t a request from the official “President of the United States” but from a “private citizen.”

The letter is so damning to Trump that we can foresee the president claiming during an impeachment trial that Giuliani was lying — back then, and even still today. That’s where Senate testimony can prove crucial. There’s a reason the Supreme Court has called live testimony, including cross-examination, “the greatest legal engine ever invented for the discovery of truth.” Put Giuliani on the witness stand — and Trump, too, if he has the guts. And let the truth come out.

All told, the documents help explain Trump’s consistent push to bury the evidence against him. Every week, it becomes clearer why Trump has withheld documents from Congress, blocked executive branch officials and even private citizens from testifying before Congress, and overall, well, obstructed Congress, as the second article of impeachment rightly describes it. It’s because Trump is a man with something to hide. Let’s see what else he’s hiding — in front of the Senate next week, in a good, old-fashioned American trial for all to see.

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