The Note: Next impeachment chapter depends on president’s men

The TAKE with Rick Klein

Loyalty has not always flowed in all directions inside the Trump White House.

Now more than ever, President Donald Trump will be counting on those he expects to be loyal to him. The short- and medium-term prospects for the impeachment inquiry depend on how top figures in the Trump administration -- and some recently departed aides -- handle requests for documents and testimony.

Secretary of State Mike Pompeo has stepped in to keep State Department officials from sitting for depositions this week. Key Democratic committee chairs responded by calling Pompeo himself a "fact witness" -- and stated that efforts to keep witnesses from talking to Congress "will constitute evidence of obstruction of the impeachment inquiry."

Attorney General William Barr and Rudy Giuliani, in his capacity as the president's personal attorney, are also wrapped up in the inquiry from multiple directions, with calls for them to appear before Congress and produce documents. Wednesday could still be a key day, with the State Department's inspector general set to brief members of Congress on an "urgent" matter related to Ukraine, ABC News has learned.

With the president intent on finding out more about the whistleblower, acting Director of National Intelligence Joseph Maguire will be a key player. Other figures whose words will be watched closely include Vice President Mike Pence and former national security adviser John Bolton.

An important signal came from Capitol Hill on Tuesday, with Sen. Chuck Grassley, R-Iowa, standing up for the whistleblower's right to remain anonymous.

"Uninformed speculation wielded by politicians or media commentators as a partisan weapon is counterproductive and doesn't serve the country," he said.

American officials serve both the government and the president, of course. That has proven a particular challenge in the Trump era.

The RUNDOWN with MaryAlice Parks

In newly leaked audio batted around online Tuesday, Mark Zuckerberg told Facebook employees the "direction of the discussion" concerning big tech in the Democratic primary was "concerning."

"At the end of the day if someone's going to try to threaten something that existential, you go to the mat and you fight," he said, promising to bring a tough legal battle should Sen. Elizabeth Warren become president and follow through on her proposal to try to break-up large technology companies like Facebook and Amazon.

Warren did not hesitate to counter-punch. She accused the company on Tuesday of running roughshod over antitrust norms.

"They've bulldozed competition, used our private information for profit, undermined our democracy, and tilted the playing field against everyone else," she wrote.

Up to this point, Warren's most aggressive plans have yet to be seriously scrutinized by either stakeholders or opponents, but you can be sure that will begin in earnest now that she's reached front-runner status. Facebook might have tested the waters, but it remains to be seen what exactly it would look like if big tech, big banks, big pharma and her big rivals lay it on thick.

The TIP with Sasha Pezenik

A new legislative session kicks into gear along with a grim milestone: Las Vegas mass shooting -- the deadliest in modern American history.

As the nation still reels from the summer's spate of mass shootings, America's gun control debate has made its way to the 2020 trail. Tuesday night, Sen. Bernie Sanders attended a memorial for the Las Vegas shooting.

On Wednesday, 10 of the Democratic primary contenders will convene in Las Vegas for a forum on gun violence -- the first of its kind for presidential hopefuls. It will be cohosted by March for Our Lives, the movement spawned from the Parkland, Florida, high school shooting, and former Rep. Gabrielle Giffords' nonprofit, in partnership with MSNBC.

But as candidates come together -- they've yet to unite in their ideas. And only one candidate has signed onto March for Our Lives' "Peace Plan" pushing for progressive gun reform: Beto O'Rourke. All 10 candidates will have to address how they'd contend with the issue as they come face to face with the people who have had to endure that fight -- and survive it -- on the front lines.

ONE MORE THING

The State Department's inspector general is expected to give an "urgent" briefing to staffers from several House and Senate committees on Wednesday afternoon about documents obtained from the department's Office of the Legal Adviser related to the State Department and Ukraine, sources familiar with the planned briefing told ABC News.

THE PLAYLIST

ABC News' "Start Here" podcast. Wednesday morning's episode features ABC News Chief White House correspondent Jonathan Karl, who tells us why Secretary of State Mike Pompeo is locked in a war of words with House Democrats over the ongoing impeachment inquiry. http://apple.co/2HPocUL

WHAT YOU NEED TO KNOW TODAY

Download the ABC News app and select "The Note" as an item of interest to receive the day's sharpest political analysis every weekday.

The Note is a daily ABC News feature that highlights the key political moments of the day ahead. Please check back tomorrow for the latest.