Does the 2020 Democratic presidential primary officially have two front-runners?

Nate Silver thinks so after a new Quinnipiac poll released Wednesday shows Sen. Elizabeth Warren (D-Mass.) pulling ahead of former Vice President Joe Biden. This is the first time Biden has lost his first place position since Quinnipiac in March began asking its question about candidate preference.

In the poll, Warren gets 27 percent support from Democratic voters, with Biden getting 25 percent support. For Warren, that's an eight point jump since Quinnipiac's August national poll, while for Biden, it's a seven point slip. Warren and Biden are now in a statistical tie.

Silver notes that while last week, he was thinking of the race as being Biden at "1a" and Warren at "1b," her latest polling has him already abandoning this distinction, and he's now ready to declare them "co-frontrunners." In addition to this Quinnipiac national poll, Warren also lead Biden in new polls this week in Iowa and New Hampshire.

Quinnipiac's polling analyst, Tim Malloy, came to a similar conclusion, saying, "We now have a race with two candidates at the top of the field, and they're leaving the rest of the pack behind." After Biden, there's a nine-point gap before Sen. Bernie Sanders (I-Vt.), who is at 16 percent. No one else cracks 10 percent support.

Quinnipiac's poll was conducted by speaking to 561 registered Democratic and Democratic-leaning independent voters nationwide from Sept. 19-23. The margin of error is 4.9 percentage points. Read the full results at Quinnipiac. Brendan Morrow

The House impeachment prosecutors spent their second of three days of arguments at President Trump's Senate trial making their case that Trump abused his power and the Constitution and must be removed from office for those abuses. To help make their case, the Democratic managers used video clips to make virtual witnesses of Sen. Lindsey Graham (R-S.C.), a member of Trump's legal team, and the president's hand-picked FBI director, attorney general, former top Russia advisers, and former homeland security adviser.

It was, in other words, "Trolling Day at the Trump trial," writes Susan Glasser at The New Yorker. But in prebutting the Trump legal team's telegraphed defense that Trump did nothing wrong, much less impeachable, "the best witnesses they called were all the president's men," not "#NeverTrump Republicans or Democrats. They were senior officials in the Trump Administration. It was devastating."

But after two days of sitting down and listening for hours at a time, the senator-jurors were getting increasingly restless, flouting rules against leaving the chamber, talking to colleagues, and using electronic devices during the House impeachment managers' presentations. So the managers threw in some jokes. "Well, you've got to give Donald Trump credit for this: He has made a religious man out of Vladimir Putin," Rep. Adam Schiff (D-Calif.) said at a one point. Rep. Hakeem Jeffries (D-N.Y.) also got a laugh after suggesting the Senate might at least subpoena the Baseball Hall of Fame to figure out which one person voted against Derek Jeter.

You can watch highlights of the eight-plus hours of arguments, collected by PBS NewsHour.

The Democratic impeachment managers have eight hours left to present their case on Friday, then Trump's team starts its rebuttal on Saturday morning. Peter Weber

Sen. Kamala Harris (D-Calif.) is seriously contemplating endorsing former Vice President Joe Biden, several Democratic officials with knowledge of the matter told The New York Times.

Harris dropped out of the 2020 Democratic presidential race in December, and although she sparred with Biden during debates last summer — most famously when she criticized him for once opposing school busing — they are back on good terms and talk often, the officials said.

She likely won't announce an endorsement until after President Trump's Senate impeachment trial is over, the Times reports, and she understands the importance of her decision, especially since two of her fellow female senators — Elizabeth Warren of Massachusetts and Amy Klobuchar of Minnesota — are also still in the presidential race.

Biden has said he "of course" would consider asking Harris to join his ticket if he is the Democratic nominee. By giving him an endorsement, it could secure her spot as his running mate — or, if he chooses someone else to be vice president, his administration's attorney general. Catherine Garcia

Donald Trump has been a public figure for 40 years, and House impeachment lead prosecutor Adam Schiff (D-Calif.) drew on America's familiarity with the president's personal brand in Thursday's nights closing arguments in Trump's Senate impeachment trial. Schiff and his fellow House impeachment managers had spent the afternoon and evening making their case that Trump is guilty of abuse of power, and Schiff addressed the elephant in the room: "Okay, he's guilty. Does he really need to be removed?"

His answer was yes, and the Senate jury already knows why.

"No one is really making the argument 'Donald Trump would never do such a thing!'" Schiff said. "Because of course we know that he would, and of course we know that he did," even if "we can't say it publicly." He continued:

And this is why he needs to be removed: Donald Trump chose Rudy Giuliani over his own intelligence agencies. He chose Rudy Giuliani over his own FBI director. He chose Rudy Giuliani over his own national security advisers. When all of them were telling him this Ukraine 2016 stuff is kooky, crazy Russian propaganda, he chose not to believe them, he chose to believe Rudy Giuliani. That makes him dangerous to us, to our country. ...

Why would anyone in their right mind believe Rudy Giuliani over Christopher Wray? Because he wanted to, and because what Rudy was offering him was something that would help him personally, and what Christopher Wray was offering him was merely the truth. What Christopher Wray was offering him was merely the information he needed to protect his country and its elections. But that's not good enough. What's in it for him? [Rep. Adam Schiff, Trump impeachment trial]

Schiff gave some hypothetical examples. If Russia "starts blatantly interfering in our election again to help Donald Trump, can you have the least bit of confidence that Donald Trump will stand up to them and protect our national interest over his own personal interest?" he asked. "You know you can't! Which makes him dangerous to this country." And if China starts helping Trump's campaign, covertly or overtly, Schiff said, "you think he's gonna call them out on it? Or you think he's gonna give them a better trade deal?" The "sad truth," he told the senators, is "you know you can't count on him" to put his country before himself.

The praise for Schiff's oratory was effusive, but not universal. "I think people on our side were absolutely offended by what he had to say," Sen. John Barrasso (R-Wyo.) told reporters afterward. Peter Weber

Don't call into question the patriotism of a Purple Heart recipient and expect to walk away unscathed.

On Thursday, Sen. Marsha Blackburn (R-Tenn.) tweeted several inflammatory things about Lt. Col. Alexander Vindman, the director of European Affairs for the White House National Security Council. Vindman was on President Trump's July 25 phone call with Ukrainian President Volodymyr Zelensky, and while testifying before House impeachment investigators, Vindman said he was troubled by Trump's request that Ukraine open an investigation into former Vice President Joe Biden, and knew he had to inform superiors.

During the afternoon's impeachment proceedings, Rep. Adam Schiff (D-Calif.) called Vindman an "American patriot," which led to Blackburn tweeting, "How patriotic is it to badmouth and ridicule our great nation in front of Russia, America's greatest enemy?"

Vindman's lawyer David Pressman reacted swiftly, saying in a statement, "This difficult moment in our country calls for seriousness and seriousness of purpose. Lt. Col. Alexander Vindman has sacrificed enormously for our country. He believes in our country. And he believes in our country's great institutions, including the United States Senate." Vindman served in the Iraq War, and received a Purple Heart for injuries he sustained in an IED attack.

"That a member of the Senate — at a moment when the Senate is undertaking its most solemn responsibility — would choose to take to Twitter to spread slander about a member of the military is testament to cowardice," Pressman continued. "While Sen. Blackburn fires off defamatory tweets, Lt. Col. Vindman will continue to do what he has always done: serve our country dutifully and with honor." Catherine Garcia

Sen. Lindsey Graham (R-S.C.), a juror in President Trump's impeachment trial, is offering free legal advice to his counsel, if they want to accept it.

So far, the House impeachment managers have "done a good job" of "painting ... a tapestry, taking a series of events and telling a story," Graham told reporters on Thursday. When Trump's legal team starts delivering his defense on Saturday, they will "start pulling on the threads."

Graham also thinks Trump's attorneys will need to shift the focus to former Vice President Joe Biden and his son, Hunter Biden. Hunter Biden was on the board of Burisma, a Ukrainian gas company, and is in the center of a debunked conspiracy theory being peddled by Trump allies, including Rudy Giuliani. Graham said Trump's team needs to "really go hard at the idea that when they tell you there's not a scintilla of evidence, groundless, baseless, phony accusations regarding the Bidens, I would challenge that very hard." Catherine Garcia

During Thursday's impeachment trial, House managers made their case before the Senate that President Trump's conduct amounted to an abuse of power.

The House prosecutors argued that when it came to Ukraine, Trump didn't care about corruption — he just wanted Ukrainian President Volodymyr Zelensky to announce an investigation of his political rival, former Vice President Joe Biden. To make this happen, Trump held out on having a meeting with Zelensky and froze approved military aid to Ukraine. This was all done "in the interest of just one person: Donald J. Trump," Rep. Zoe Lofgren (D-Calif.) said.

In his closing statement, Rep. Adam Schiff (D-Calif.) said when the managers are done presenting their case, they will have proven "overwhelmingly" that Trump is guilty. "That is, he's done what he's charged with," Schiff said. "He withheld the money. He withheld the meeting. He used it to coerce Ukraine to to do these political investigations. He covered it up. He obstructed us. He is trying to obstruct you. And he's violated the Constitution."

"If the truth doesn't matter, we're lost," he continued. "The framers couldn't protect us from ourselves if right and truth don't matter. But here, right is supposed to matter. It's what made us the greatest nation on earth. No Constitution can protect us if right doesn't matter any more. And you know, you can't trust this president to do what's right for this country." Catherine Garcia