What did Sens. Elizabeth Warren (D-Mass.) and Bernie Sanders (I-Vt.) say to each other during their tense post-debate exchange?

That remains a mystery, but Sanders' campaign manager, Faiz Shakir, has provided a bit more information, telling The Washington Post on Wednesday that Warren approached Sanders after the Democratic debate to "raise a concern."

This exchange between Sanders and Warren became one of the evening's most talked-about moments, primarily because Warren seemed to rebuff Sanders as he reached out for a handshake. The two then shared a few words that couldn't be heard on television but that appeared far from friendly. Although billionaire Tom Steyer was standing nearby, he told CNN he didn't really listen to the conversation.

After Warren raised this unspecified concern, Sanders said "let's talk about that later," Shakir told the Post.

Although Shakir didn't explain what Warren's "concern" was, one would assume their conversation had something to do with their ongoing dispute about a 2018 conversation in which Warren claims Sanders said a woman couldn't be elected president in 2020. Warren said during Tuesday's debate she "disagreed" when Sanders allegedly said this, although she wasn't directly asked whether he did.

Sanders has said he did bring up during the conversation with Warren that President Trump, a "sexist," would "weaponize whatever he could" in 2020. But he has denied claiming a woman couldn't win, saying during the debate, "Anybody who knows me knows that it’s incomprehensible that I would think that a woman cannot be president of the United States." Brendan Morrow

During the most recent Democratic presidential debate, Sen. Elizabeth Warren (D-Mass.) had a memorable zinger when the conversation inevitably turned to the question of her electability. "Can a woman beat Trump?" Warren asked. "Look at the men on this stage. Collectively, they have lost 10 elections. The only people on this stage who have won every single election that they have been in are the women. Amy [Klobuchar] and me."

It seems The New York Times took that to heart.

For the first time ever, the paper's editorial board endorsed not one but two presidential candidates on Sunday: Warren and, you guessed it, Minnesota Sen. Amy Klobuchar. In its announcement, the Times appeared torn, as many voters are, between "the radical and the realist models" on display within the Democratic field. But the paper said "Ms. Klobuchar and Ms. Warren right now are the Democrats best equipped to lead that debate."

While pushing back on more "radical" ideas of Warren's, "like nationalizing health insurance or decriminalizing the border," the paper's editorial board said her ideas "have matched the moment." It praised her anti-corruption legislation, along with her proposals on housing reform, energy policy, social security expansion, and childcare and education.

Meanwhile, the board called Klobuchar "a standard-bearer for the Democratic center" and applauded her long history as a lawmaker, noting she is "the most productive senator among the Democratic field in terms of bills passed with bipartisan support." The board was less enthusiastic about concerning reports about Klobuchar's management style. But otherwise it had very little criticism of her, aside from acknowledging "she has struggled to gain traction on the campaign trail."

The paper said its decision was likely to leave some readers "dissatisfied," and indeed, the blow back has already begun. You can read the entire endorsement — or rather, endorsements — at The New York Times. Jessica Hullinger

Former New York City Mayor Rudy Giuliani claims he'd "love" to be a witness in President Trump's Senate impeachment trial, reports The Hill.

Giuliani, who serves as Trump's personal lawyer, told radio talk show host John Catsimatidis: "I would love to see a trial. I'd love to be a witness — because I'm a potential witness in the trial — and explain to everyone the corruption that I found in Ukraine, that far out-surpasses any that I've ever seen before, involving Joe Biden and a lot of other Democrats."

Giuliani was allegedly involved in a push to pressure Ukraine into launching investigations into Trump's political rivals, working to dig up dirt on former Vice President Joe Biden and pushing out former Ukrainian Ambassador Marie Yovanovitch, who was reportedly viewed as an obstacle in obtaining the promise of investigations.

Democrats in Congress have called for the Senate impeachment trial, set to begin arguments this week, to include additional witnesses beyond those who testified in the House inquiry. Senate Republicans have so far declined the requests. No evidence has emerged to prove any wrongdoing by Democrats in Ukraine, but Giuliani said "I have those facts. I have those witnesses. I have documents, and I have recordings. And I would love to get them out in public." Summer Meza

House Intelligence Committee Chair Adam Schiff (D-Calif.) on Sunday accused the National Security Agency of withholding key documents from Congress related to Ukraine that could be relevant in President Trump's impeachment trial.

Speaking to ABC News, Schiff said the NSA appears "to be succumbing to pressure from the administration," also saying "there are signs that the CIA may be on the same tragic course." Schiff said the documents could be important to the central allegation of Trump's impeachment: that he abused his power by withholding Ukraine military aid to push the country into announcing investigations of his political rivals.

The NSA and CIA have not commented on Schiff's allegations, reports NBC News.

Read more at NBC News and ABC News. Summer Meza

Fox News' Chris Wallace pointed out Sen. Lindsey Graham's (R-S.C.) updated view on witnesses in a Senate impeachment trial, but Graham swore the situation is now different.

House Democrats say "evidence overwhelmingly establishes" Trump's guilt ahead of his Senate impeachment trial, set to begin arguments on Tuesday. But they want to call new witnesses to testify, including former National Security Adviser John Bolton and Lev Parnas, an associate of Rudy Giuliani. Senate Republicans have so far denied the request.

Wallace said Graham's view that new witnesses should not appear "directly contradicts what you said as a Republican House impeachment manager in 1999 during the Clinton impeachment trial." At the time, Graham said "there may be some conflict that has to be resolved by presenting live witnesses. That's what happens every day in court and I think the Senate can stand that."

"Why were witnesses okay then, but they're over the line now?" asked Wallace.

Graham blamed the "railroad job" in the House, saying witnesses were available before the House voted to impeach Trump. "If they were that important, why didn't you call them in the House? Do you need them to make your case?" The Hill reports that in some cases, witnesses were not available or willing to testify until very recently. The White House also blocked several administration officials from appearing before the House. Summer Meza

House Democrats filed a 111-page legal brief ahead of President Trump's impeachment trial, arguing he threatens national security.

The House prosecutors laid out the argument against Trump that led to his impeachment last month on charges of abuse of power and obstruction of Congress. The legal brief says "evidence overwhelmingly establishes" Trump's guilt and says the Senate "must eliminate the threat" he poses.

The White House defense team, meanwhile, has not filed its official brief, but rejected the impeachment managers' arguments as "highly partisan." Without directly addressing allegations Trump abused his power by withholding Ukrainian aid to push for a politically-motivated investigation of his rivals, the White House castigated the "lawless process" that led to his impeachment.

Read more at The Washington Post. Summer Meza

Hong Kong protesters were hit with tear gas and pepper spray after demonstrators allegedly attacked a plainclothes police officer during a mass protest, reports The Washington Post.

Demonstrations have been ongoing for months, and have recently erupted in occasional violence as pro-democracy residents continue to protest the local government. Several protesters were arrested on Sunday after tens of thousands participated in a rally in Hong Kong's central district, the largest demonstration since New Year's Day when over a million people gathered.

A plainclothes officer reportedly refused to show a rally organizer his identification card, which led to an altercation. At least three people were injured. Read more at The Washington Post. Summer Meza