Today, it starts getting serious. House Judiciary Committee Chairman Jerry Nadler is sending out letters to around 60 people in the Trump administration and the president’s general orbit (Don Jr., Allen Weisselberg) seeking documents and other information to “begin investigations to present the case to the American people about obstruction of justice, corruption and abuse of power,” as he put it on ABC’s This Week.

I’ve known Nadler since 1987, back in my cub reporter days. He was in the New York State Assembly then, and it didn’t take long for me to figure out he was one of the smartest politicians I’d encountered. He knew history, ideas, and the law. I won’t bore you with the details, in part because I’m not sure I remember them all, but there was a little controversy in Greenwich Village politics in those days involving the competition between the two Village Democratic clubs, one pretty left-leaning (and opposed to then-Mayor Ed Koch), the other a pro-Koch club.

Nadler was himself anti-Koch, but he spoke up in defense of the pro-Koch club, which wasn’t sitting very well with me at first, but I remember when I interviewed him about it I put down the phone admitting to myself that his legal reasoning was precise and unassailable. I was impressed with his insistence on due process even when it didn’t lead to the end point that would have been more politically popular with his constituents.

That’s exactly the kind of person who ought to be chairing the House Judiciary Committee. As I write these words on Sunday, we don’t yet know who the 60 people are or exactly what the letters say. But I think we can make some pretty safe educated guesses about both.

Aside from the two aforementioned and former Trump aides John Kelly and Don McGahn, whom Nadler named on TV, it would seem likely that letters would go to Jared Kushner, Stephen Miller, Sarah Huckabee Sanders, and some campaign aides. There’s also a fair chance they’d go to Ivanka and other current and former members of the Trump Organization.

As for what he’ll be looking into, let’s start with obstruction of justice. Something weird has been happening over the last few weeks. As we prepare for the Mueller report, this odd bit of conventional wisdom seems to have settled in that if Robert Mueller finds no smoking gun on collusion, and has “just” obstruction, it won’t be a big deal.

Um, excuse me. Obstruction of justice is a crime. It’s serious. It was enough to chase Richard Nixon from office. We never knew (and still don’t know!) whether Nixon had advance knowledge of the Watergate break-in, but Congress did establish that he attempted to obstruct justice, and boom, he was out.

To the Republican Party of 1974, that was crime enough for a man not to deserve to occupy the presidency. That somehow obstruction of justice isn’t a big deal today is the 568th manifestation of the ways in which Donald Trump and the Republican Party that so fulsomely supports him have debased our political culture.

It’s partly because our imaginations naturally move toward the most salacious possible outcome, in which context “mere” obstruction would be a disappointment; and it’s partly because any sentient, honest person already knows Trump obstructed justice. He does it on television and Twitter on a weekly basis. But the fact that he does it in plain sight doesn’t make it any less serious.

Since Nadler’s jurisdiction is the Constitution, I’d expect he’ll also be digging into violations of the emoluments clause. Trump has done nothing to separate himself from his business. This is another one of these “in broad daylight” things that should have been a huge scandal from the day Trump took office. But as long as the Republicans were running Congress, it all went unpursued.

Well, that changes, starting today. And what a change! Last week wasn’t just a bad week for Trump, as many commentators noted. It was a humiliating week for the United States of America.

The president went over to Vietnam with no preparation, no knowledge, no anything except his puffy ego and his conviction that he could cut a deal because he was offering Kim something new. If he ever read anything, he’d have known that he wasn’t offering anything new at all.

Lifting sanctions for full de-nuclearization has been U.S. policy for ages, under presidents of both parties. The man’s an idiot. And on top of that we had to endure the spectacle of Trump lavishing that sickening praise on the head of the world’s most oppressive regime, a man who kills his own people (from a 2014 UN report: Kim’s regime “caused the death of at least hundreds of thousands of people and inflicted permanent physical and psychological injuries on those who survived”). And the president of the United States says, “Why shouldn’t I like him?”

Just imagine the reaction if Barack Obama had ever said those words. And, of course, we also had Michael Cohen’s testimony. I kept stopping and saying to myself: This man is talking about the president. He sounds like he’s talking about Vito Corleone.

And let’s not forget that was all topped off by that lunatic speech at CPAC. We’re way past being shocked anymore, but yes, it’s disgraceful for a president to use the word “bullshit” in public (a point on which Republicans would howlingly agree if Obama had ever done it).

But that was then. This week, finally, the defense of the Constitution begins.