President Trump loves superlatives, so here’s one: His July 25 conversation with Ukrainian President Volodymyr Zelensky may have been the single dumbest, most damaging phone call in the history of the presidency, if not in the history of telephonic communication itself.

Without that phone call, Trump would almost certainly not be on the road to impeachment right now. And yet, somewhere in his addled mind he still believes it was, in the word he has used so many times, “perfect.”

“Everybody knows I did nothing wrong,” Trump said in a new interview. “Bill Clinton did things wrong; Richard Nixon did things wrong," Trump continued. "They did things wrong. I did nothing wrong.”

In reality, when the history of the Trump impeachment is written, we’ll look back and say it all could have been different if he just decided not to pick up the phone that day.

That isn’t to say that his actual impeachable offenses, even just with regard to Ukraine, were restricted to that call. As we now know, he set up an entire shadow foreign policy run through his deranged “personal lawyer” Rudy Giuliani, the purpose of which was to pressure the Ukrainian government to open an investigation that could be used to damage Joe Biden.

This shadow foreign policy circumvented most of the professionals in the White House, Pentagon and State Department, and put power in the hands of people such as Ambassador to the European Union Gordon Sondland, who wasn’t responsible for Ukraine but was being told by Trump what to do.

So The Call was only one episode in the effort. But here’s what’s so critical about it: Had Trump not made The Call, we probably never would have found out about how Ukraine policy was being twisted to support Trump’s reelection.

Remember, what tipped the scales toward an impeachment inquiry was the complaint filed by the whistleblower; The Call was the centerpiece of that complaint. No call, no whistleblower complaint, no public knowledge of the shadow effort to press the Ukrainians on Biden, and no impeachment.

What has become clear as more people have testified is that The Call set off a frenzy of activity in the White House. One after another, officials have testified that reaction to The Call was somewhere between concern and panic.

Despite all that, Trump decided to release a partial transcript of The Call, in the apparent belief that it would exonerate him. Instead, it sealed his fate.

There is a gap in our knowledge of this story: We don’t know exactly how the decision was made by the White House to release the transcript. We did learn that Senate Majority Leader Mitch McConnell urged Trump to release it, but in the end such a momentous decision could only have been Trump’s alone, whether it was his idea in the first place or not. One has to imagine that anyone around him with the political sense of a turnip would have objected, but we just don’t know.

But in the end, that decision might not have mattered. Once news of what happened on The Call began to leak out, if Trump hadn’t released a transcript, Democrats would have eventually subpoenaed it.

Curious about what would have happened next, I reached out to a number of law professors and experts in presidential power, and they all told me the same thing: While Trump might have been able to exert some variant of executive privilege and claim that a president’s conversations with foreign leaders should be secret, he would almost certainly have lost in court.

While the existence of such a privilege covering conversations with foreign leaders might be reasonable in the abstract (even if it’s not written explicitly into law), you can’t assert executive privilege to cover up a crime or an impeachable offense. Once news of The Call was public, there was ample reason to suspect that misdeeds had occurred on it. At that point, Trump would not be able to keep it secret.

Not that he wouldn’t try. In their never-ending task of shielding him from scrutiny, Trump’s lawyers regularly make sweeping claims about his immunity from law, oversight and investigation that leave judges positively gobsmacked. So Trump might have been able to drag things out while the case went up to the Supreme Court, but eventually he’d lose, just as Richard Nixon did when trying to conceal the White House tapes.

Which means that the moment Trump set the phone down in its cradle, the die was cast. He probably leaned back in his chair, a self-satisfied smile on his face, and said to himself, “What a perfect call. Really tremendous. Platinum-quality.”

At that very moment, White House officials were in a state of severe distress, trying to figure out the ramifications of what he had just done and how bad the damage would be. And impeachment became all but inevitable.

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