Over the past week, Facebook and Twitter codified two classes of free speech — one set of rules for politicians and "world leaders,” and another for the rest of us, Axios' Scott Rosenberg writes for our series, "Misinformation age."

• Why it matters: Social media platforms are privately owned spaces that have absorbed a huge chunk of our public sphere. The rules they're now hashing out will shape the information climate around elections for years to come.

Why now? President Trump's campaign placed ads this month that made false statements about Joe Biden.

• Biden's campaign asked media outlets and digital platforms to stop running the ads. CNN took them down; Facebook kept them up.
• Then Sen. Elizabeth Warren provoked Facebook with a deliberately misleading Facebook ad that claimed the company had endorsed Trump — before admitting that was a ruse to expose flaws in Facebook's policy.
• Facebook kept that ad up, too.
• Over on Twitter, Sen. Kamala Harris is demanding that Trump's account get the boot for his repeated attacks on the Ukraine whistleblower and others.

How it works on Facebook:

• Facebook's policy lets politicians make just about any factual claim they want, in ads or posts, including repeating verbatim a false claim that has already been labeled elsewhere as false.
• That means they can misstate their own record or that of an opponent.
• They can't misstate details about the voting process, such as when an election is taking place, the rules or how to vote.
• Their ads can't include profanity, as Trump's campaign found out.
• They can't embed social media posts that have been flagged by a fact checker.

How it works on Twitter:

• Twitter defines a class of "world leader" users who "are or represent a government/elected official, are running for public office, or are being considered for a government position," and who also have more than 100,000 followers and are verified.
• In theory, world leaders are supposed to follow rules that apply to everyone else. That would mean no threats of violence, no promoting terrorism, no engaging in targeted harassment, and no harassing people of a particular race, religion, sexuality or gender.
• But Twitter says it may leave up the posts even if politicians break the rules due to the "newsworthiness" of their comments.

Go deeper: Read earlier installments in our series, "The misinformation age."

Besieged by Republican criticism, President Trump tweeted at 9:52 p.m. that he was abandoning his plan to hold next year's Group of 7 economic summit at his own Trump National Doral resort near Miami.

• "We will begin the search for another site, including the possibility of Camp David, immediately. Thank you!"
• He blamed "Media & Democrat Crazed and Irrational Hostility."

Why it matters: The self-dealing could have inspired an extra article of impeachment, lawsuits, demands for forensic accounting, boycotts by world leaders, defections by Republicans and other consequences Trump can't afford.

Historian Ron Chernow says Alexander Hamilton — author of the 11 "Federalist" essays on powers of the presidency, and the first Treasury secretary — "would most certainly have endorsed the current impeachment inquiry."

• Chernow — whose biography "Alexander Hamilton" gave us the musical "Hamilton" — writes on the cover of the WashPost's Outlook section: "Hamilton pushed for impeachment powers. Trump is what he had in mind."
• "He wanted a strong president — and a way to get rid of the demagogic ones."

A boy stands in line as people receive aid donated by the Turkish Red Crescent in the border town of Tal Abyad, Syria.

"Americans Now Need at Least $500,000 a Year to Enter Top 1%," Bloomberg reports:

• "The income needed to exit the bottom 99% of U.S. taxpayers hit $515,371 in 2017," according to IRS data released last week.

"While the Trump campaign has put its digital operation firmly at the center of the president’s re-election effort, Democrats are struggling to ... adapt to a political landscape shaped by social media," the N.Y. Times' Matt Rosenberg and Kevin Roose write in today's lead story.

• Why it matters: "Interviews with Democratic consultants and experts revealed a party deeply hesitant to match the Trump campaign’s intense and often angry partisan approach."

The big picture: "For the left, the Trump campaign’s mastery of social media in 2016 represented a sharp reversal. From the blogs of the mid-aughts to Netroots Nation, the digital activists who helped propel Barack Obama to victory in 2008 and 2012, the left was seen as the dominant digital force."

After a heart scare, Bernie Sanders vowed that he's "more ready than ever" to fight for political revolution. "To put it bluntly, I am back," Sanders declared, sparking chants of "Bernie is back" from the massive crowd in a Queens park. (AP)

• Rep. Alexandria Ocasio-Cortez and filmmaker Michael Moore both endorsed the Vermont senator.
• "He took the stage clad in black to loud cheers and the strains of AC/DC’s 'Back in Black.'" (Bloomberg)

A security company hired by the campaign reported a crowd estimate of 25,000.

• Elizabeth Warren’s campaign said her crowd last month in Washington Square Park in Manhattan exceeded 20,000.

Hillary Clinton's suggestion that Rep. Tulsi Gabbard (D-Hawaii) is being "groomed" by Russians to act as a 2020 spoiler has inspired more interest in Gabbard's longshot candidacy, AP's Alexandra Jaffe reports from Iowa.

• Clinton appeared on David Plouffe's "Campaign HQ" podcast, where she did not mention the congresswoman by name, but said Russians have "got their eye on somebody who's currently in the Democratic primary and are grooming her to be the third party candidate."

Gabbard refused to disavow the support she's seen from Russian actors and alt-right sites.

Rebecca Shelp of Littleton, Colorado, bought her 14-year-old son a used iPhone 7 and set up Screen Time to limit his use of apps and social media, the WashPost's Reed Albergotti writes.

• "But her son figured out workarounds almost immediately. ... [H]e simply reset the phone, set up a new Apple ID and used whatever he wanted for as long as he wanted."

"Shelp found out when she inspected his phone."

• "She says her son figured out how to make Screen Time glitch out by turning the phone off and on constantly until it stopped working properly."
• "Her son even coined a term for this: 'colliding the system.'"

The World Series starts Tuesday night at the Astros' Minute Maid Park in Houston, then comes to Washington's Nationals Park on Friday night.

• See the schedule.

In this Year of the Home Run, the focus of the 2019 Fall Classic is on the mound, AP's Ben Walker writes in his lookahead:

• A throw-down for the ages, maybe.
• Astros pitcher Gerrit Cole is lined up for Game 1, with Justin Verlander and Zack Greinke to follow.
• For Nats Nation, it's Max Scherzer, Stephen Strasburg and Patrick Corbin. And even Aníbal Sánchez — all he's done lately is take a playoff no-hit bid into the eighth inning.

Houston opened as a 2-1 favorite of the Las Vegas sports books.

• The Astros are trying to take their second crown in three years, while the wild-card Nationals are making their Series debut.
• Nats have six days off after the Tuesday finish to their sweep of the St. Louis Cardinals in the National League Championship Series.