A national progressive group, Indivisible, is asking the 20 candidates in the Democratic presidential race to sign a pledge promising a positive, “constructive” primary that ends with all participants coming together to support the eventual nominee — “whoever it is — period,” BuzzFeed News reports.

CNN: “As Biden finally jumped into the 2020 presidential race Thursday, his decision not to challenge Hillary Clinton for the Democratic nomination in 2016 is among the factors fueling his candidacy now.”

“For the last four years, Biden has never fully reconciled with his choice. It’s a decision Obama and his top aides helped steer him toward… But this time around, Obama didn’t urge Biden to stay on the sidelines and watch as the largest and most diverse field in the history of the Democratic Party took shape.”

“People think Iowa and New Hampshire are the first test. It’s not. The first 24 hours. That’s the first test. Those are way down the road. We’ve got to get through this first.”

— Joe Biden, quoted by Politico, on the importance of early fundraising.

Vox: “The next time a new national 2020 poll comes out, you can probably fill in the blanks yourself: Biden at 30 percent, give or take, Sanders trailing 5-10 points behind him, Harris and now Buttigieg both hanging around at 10 percent. O’Rourke in there somewhere, Warren at 5 percent or 6-ish, and then a crowd of Booker, Buttigieg, Klobuchar, Castro, and Kirsten Gillibrand with maybe a few percentage points each.”

“The story has barely changed all year. The big unknown is how durable Biden’s stubbornly consistent lead really is — but we should start getting a better idea now that he’s finally officially announced his candidacy. And even then, things may not really change until the first round of debates, when the public turns its full attention to the presidential campaign.”

Harvard Political Review: “As parties become increasingly polarized, Democratic Party leadership seems focused on finding a candidate who can win. Moving into the 2020 primary season, the question on many left-leaning minds is not which candidate stands on the best policies but rather, who can beat Donald Trump.”

“Though this approach may seem like savvy strategy in the short term, candidates seeking to garner the youth vote may benefit more from following trends in youth political attitudes than trends in electability. A poll organized by the Harvard Public Opinion Project indicated that 82 percent of millennial respondents believe that it is more important for a candidate to share his political views than to be an electable politician. Across all demographics, youth support for candidates who share their political perspectives never falls below 75 percent of respondents.”

Aaron Blake: “From start to finish, Biden’s announcement video is about Trump and preventing his presidency from being prolonged beyond 2020.”

“It’s a striking departure from his foes for the 2020 Democratic nomination — and from how Democrats ran in the 2018 midterm elections. Even as Trump was broadly unpopular, their campaign messaging really wasn’t about Trump, at least in the general election.”

NBC News: “The Mueller report’s narrative of secret meetings between members of Donald Trump’s orbit and Russian operatives — contacts that occurred both before and after the 2016 election — portrays a political campaign that left itself open to a covert Russian influence operation, former intelligence officials and other experts say.”

“While finding no criminal conspiracy, the report shows that Trump associates met with Russians after the intelligence community said in October 2016 that Russia was interfering in the presidential election, and even after the Obama administration announced a set of post-election sanctions to punish Russia for that behavior.”

Nate Silver: “His case to win the 2020 Democratic nomination is fairly simple: As Barack Obama’s two-term vice president, he’s the most familiar brand in the field. He’s ahead in the polls (it’s emphatically not a tie for the lead with Bernie Sanders; Biden’s polling is quite a bit better). He’s also the best-performing Democrat in polls against President Trump, and he gains a lot of support from Democrats on the basis of his perceived electability. And while he might not be the most liberal Democrat, that isn’t necessarily a disadvantage; roughly half of voters in the Democratic primary identify as moderate or conservative, which could be a plus in a field where many candidates are running to the left.”

“Of course, this doesn’t mean Biden’s path to the nomination is easy. Not by a long shot. But before we start to poke holes in Biden’s candidacy, let’s ruminate on his advantages a little longer. There’s a case to be made that the media — in seeking out shiny new objects like Pete Buttigieg, and in ignoring the preferences of older, more working-class and more moderate Democrats who still make up a large part of the Democratic base — is overlooking the obvious front-runner in Biden. Arguably, in fact, media elites have the same blind spots for Biden that they had for Trump.”