There have been many holy-crap-that-did-not-just-happen days in the Trump White House. But few top the soap opera of Oct. 16, 2019 — exactly Day 1,000 of the Trump presidency.

• A GOP official in California told Axios' Margaret Talev: "The needle on the Batsh*t Crazy Meter may have gone past the red zone today."

Roll the camera:

• A one-page letter from Trump to Turkish President Recep Tayyip Erdogan (read it below) sounded fake when it first surfaced on Twitter, but was real: "Let's work out a good deal! You don't want to be responsible for slaughtering thousands of people, and I don't want to be responsible for destroying the Turkish economy — and I will. ... Don't be a tough guy. Don't be a fool! I will call you later."
• During a meeting with the congressional leadership in the Cabinet room, according to a senior Democratic aide who provided a readout, Trump said that Jim Mattis, a four-star Marine general and Trump's first defense secretary, was "the world's most overrated general. ... You know why? He wasn't tough enough. I captured ISIS. Mattis said it would take two years. I captured them in one month."
• Pelosi told reporters in the White House driveway afterward: "What we witnessed on the part of the president was a meltdown — sad to say."
• Trump tweeted: "Nancy Pelosi needs help fast! There is either something wrong with her 'upstairs,' or she just plain doesn’t like our great Country. She had a total meltdown in the White House today. It was very sad to watch. Pray for her, she is a very sick person!"
• Trump had said in the Oval Office earlier about the withdrawal from Syria that endangered our longtime allies, the Kurds: "Syria may have some help with Russia, and that’s fine. It’s a lot of sand. They’ve got a lot of sand over there. So there’s a lot of sand that they can play with. But we were supposed to be there for 30 days; we stayed for 10 years. And it’s time for us to come home. ... The Kurds are much safer right now ... They’re not angels, if you take a look."
• The House voted 354-60 to condemn Trump's decision to withdraw U.S. troops from northern Syria.

At the White House, Trump told Pelosi, according to the Democratic aide: "President Obama drew a red line in the sand. In my opinion, you are a third-grade politician."

• House Majority Leader Steny Hoyer said: "This is not useful."
• Pelosi and Hoyer stood and left the meeting.
• According to the aide, Trump as they left said: "Goodbye, we'll see you at the polls."

What's next: Vice President Pence and Secretary of State Mike Pompeo were wheels-up at 6 p.m. for a 12-hour flight to Turkey.

• Trump goes to Texas today, for a rally in Dallas tonight.

The bottom line: Day 1,000 is one they'll write books about.

House Oversight Chairman Elijah Cummings died this morning at age 68 due to longstanding health complications, writes his hometown Baltimore Sun.

• "The Democrat, known for his devotion to Baltimore and civil rights, and for blunt and passionate speechmaking, died at Johns Hopkins Hospital."
• After the 2018 midterms, "pundits had speculated ... that Cummings, who could be boisterous in his questioning of witnesses, might become a 'nightmare' for [President] Trump."

"Within the space of a few hours, advances by Turkish troops in Syria ... recalibrated the balance of power in the Middle East," writes the Washington Post's Liz Sly.

• "The [U.S.] withdrawal delivered a huge victory to Syrian President Bashar al-Assad, who won back control of an area roughly amounting to a third of the country almost overnight."
• "It affirmed Moscow as the arbiter of Syria’s fate and the rising power in the Middle East."
• "It sent another signal to Iran that Washington has no appetite for the kind of confrontation that its rhetoric suggests and that Iran’s expanded influence in Syria is now likely to go unchallenged."

"It sent a message to the wider world that the United States is in the process of a disengagement that could resonate beyond the Middle East."

Disinformation campaigns are increasingly able to find willing human participants to amplify their messages and even generate new ones on their own, writes Axios' chief technology correspondent Ina Fried.

• They're switching from employees to volunteers — and from participants who are in on the game to those who actually believe the disinformational payload they're delivering.

The "most frightening" examples, via researcher Kate Starbird, are conspiracy theories tied to mass casualty events, which crop up organically, though Russian or other disinformation promoters can and do help amplify the messages.

• "It's almost like a self-sustaining community, but you can see it's been shaped by disinformation campaigns of the past," Starbird said.

Why it matters: Understanding this changing nature is critical to preparing for the next generation of information threats, including those facing the 2020 presidential campaign.

Michael McKinley, a career foreign service officer and Secretary of State Mike Pompeo's de facto chief of staff until last week, told House investigators behind closed doors that he could no longer look the other way amid the Trump administration's dealings with Ukraine, AP reports.

• ❗"I was disturbed by the implication that foreign governments were being approached to procure negative information on political opponents," McKinley testified.

A Florida man accused of conspiring with associates of Rudy Giuliani to make illegal campaign contributions — David Correia, 44 — flew to JFK Airport in New York City to turn himself in, and was freed on bail. (AP)

The opioid crisis cost the U.S. economy $631 billion in just four years (2015-2018) — and it may keep getting more expensive, according to the Society of Actuaries.

• The biggest cost driver over the four-year period is unrealized lifetime earnings of people who died, followed by health care costs, AP's Geoff Mulvihill reports.
• Governments bear less than one-third of the cost. The rest of it affects individuals and the private sector.

More than 400,000 American lives have been lost to the opioid crisis since 2000.

Prime time, same time...

As HBO's "Silicon Valley" enters its final season, the show's tagline asks "How Big Is Too Big?" in a not-so-subtle nod to the real-life tech industry issues it's set to parody before the curtain falls.

• Why it matters: "It’s almost as if breaking all the things isn’t always a good thing — who could have foreseen?" co-creator Alec Berg told Axios' Kia Kokalitcheva of the ongoing techlash that's mirrored in the show.

What's next: The first episode dives right into it with protagonist and Pied Piper CEO Richard Hendricks, played by Thomas Middleditch, heading into a congressional hearing about Big Tech's privacy indiscretions.

This letter outlining the design for the 1951 novel "The Catcher in the Rye" is part of a J.D. Salinger exhibit that opens tomorrow, and continues through Jan. 19, at the New York Public Library's historic Fifth Avenue branch in Manhattan.

• In an early draft of the novel, narrator Holden Caulfield warns that the story will include "quite a bit of swearing and sex stuff." But Salinger drew a large "X' over the passage and wrote "delete" in the margins, AP's Hillel Italie writes.
• The display also includes family photographs, letters and other rarities from the famously reclusive author, who died in 2010 at age 91.