WASHINGTON — Some days, as we’ve written over the past few months, Democratic co-frontrunner Joe Biden looks much weaker than the conventional wisdom suggests.

Other days, he looks much more durable than what you read on Twitter.

And this week, Biden’s been in the latter category — he’s looked pretty strong when it comes to the fundamentals on paper. Certainly stronger than in his debate performances.

On Tuesday, Kamala Harris suspended her presidential campaign, underscoring Biden’s almost unmovable strength with African-American voters.

On Wednesday, his campaign released a blistering ad/video on President Trump’s reception and performance on his most recent overseas trip.

On Thursday, he picked up the endorsement from former Obama Secretary of State and 2004 presidential nominee John Kerry, who campaigns with Biden today in Iowa.

And last night, the Elizabeth Warren and Pete Buttigieg camps began to fight each other, leaving Biden above the fray (at least for now).

Speaking of the fray, however, what also stands out for Biden this week was his confrontation with that Iowa voter yesterday.

There are two ways to look at it: One, Biden took tough/hostile/inaccurate questions to an 11 on the dial, when it probably needed to be only a six or a seven. (“You're a damn liar, man...Let's do push-ups together here, man, let's run... Get your words straight, Jack.") Remember, Biden’s campaign pledge has been to offer “strong, steady, stable leadership.”

Two, he showed voters some fight that they might not have seen recently, especially when the conversation turns to his family.

Today at 5:00 pm ET is the deadline for the Trump White House to decide if it will mount a defense in the House’s impeachment inquiry, NBC’s Geoff Bennett says.

Bennett reminds us that, in his Dec. 1 letter, White House counsel Pat Cipollone refused to participate in Wednesday’s House Judiciary hearing but left open the possibility of participating in future impeachment hearings if Democrats made certain concessions.

As for yesterday’s big impeachment development, Speaker Nancy Pelosi announced that she asked key Democratic chairmen to begin drafting articles of impeachment against President Trump.

“Sadly, but with confidence and humility, with allegiance to our founders and our heart full of love for America, today, I am asking our chairmen to proceed with articles of impeachment,” she said, per NBC News.

Tweet of the day

If you are telling Dem strategists that OK-05 (Trump+14, Romney+19) is 45% pro-impeach, I'm guessing they are going to feel pretty darn good about holding the majority. https://t.co/T6Yx76Uv9F — Mike DeBonis (@mikedebonis) December 5, 2019

2020 Vision: Warren vs. Buttigieg — it’s on

After polls showing how Pete Buttigieg has eaten into Elizabeth Warren’s earlier support among white Democrats with college degrees, the two campaigns began engaging on Thursday – 60 days out from the Iowa caucuses.

Asked by reporters whether Buttigieg should release more information from his time as a consultant at McKinsey, Elizabeth Warren responded with an eager yes, per NBC’s Deepa Shivaram.

“I think that voters want to know about possible conflicts of interests. It is even more important that the candidates expose possible conflicts of interests right now and that means for example, that the mayor should be releasing who is on his finance committee; who are the bundlers who are raising big money for him; who he has given titles to and made promises to. And he should open up the doors so that the press can follow the promises that he is making in these big-dollar fundraisers.”

Top Buttigieg communications adviser Lis Smith fired back, “If @ewarren wants to have a debate about transparency, she can start by opening up the doors to the decades of tax returns she’s hiding from her work as a corporate lawyer – often defending the types of corporate bad actors she now denounces.”

On the campaign trail today: It’s another big day in Iowa

Joe Biden stumps with John Kerry… Pete Buttigieg, Bernie Sanders, Cory Booker, Amy Klobuchar and John Delaney all attend a farmers union presidential forum in Grinnell… And Buttigieg, Klobuchar, Julian Castro and Tom Steyer attend a U.S. Conference of Mayors forum in Waterloo… Before he’s in Iowa, Buttigieg stumps in New Hampshire… As do Elizabeth Warren, Tulsi Gabbard and Michael Bennet… Michael Bloomberg speaks with CBS’ Gayle King… And Andrew Yang raises money in Dallas.

Dispatches from NBC’s campaign embeds

While campaigning in New Hampshire, Tulsi Gabbard was indirectly asked about rhetoric that’s inferred she’s a preferred candidate of leaders like Vladimir Putin, NBC’s Julia Jester reports:

Gabbard: We are at great risk of nuclear catastrophe but there is no shelter. Within my first week as President, I will call for a summit between the United States and Russia and China to begin the talks necessary to deescalate these tensions [applause] and work to end this new cold war to begin to try to put back together some of these treaties that were put in place to reduce the number of nuclear weapons in the world that have been so eroded or torn apart or thrown in the trash can --

Audience member: They're gonna call you a Russian.

Gabbard: They already are.

Audience member: I know.

Gabbard: My interest is the safety, security, and future of the American people and it doesn't matter what kind of rhetoric is being put out, nothing will detract me from that mission.

And a confirmation from three of our embeds: Jester, Gary Grumbach and Amanda Golden — Bernie Sanders will receive an endorsement from the New Hampshire Postal Union on Friday. It will be the second largest union to endorse Sanders so far this cycle.

Data Download: The number of the day is … three

Just three.

That’s the number of House Democrats who have endorsed Pete Buttigieg. No U.S. senators or governors have said they’re backing him so far, either, putting the South Bend mayor significantly behind his fellow top Democratic contenders in the endorsement race.

More, from NBC’s Sami Sparber: “Former Vice President Joe Biden leads the field, with 30 total endorsements from House members, senators and governors, according to NBC News’ tally of FiveThirtyEight’s endorsement tracker. Meanwhile, the other members of the Top 4 – Massachusetts Sen. Elizabeth Warren and Vermont Sen. Bernie Sanders – clock in at 12 and six major endorsements, respectively. Before she dropped out of the race Tuesday, California Sen. Kamala Harris had racked up 19 major endorsements, putting her in second place. With 13 endorsements, New Jersey Sen. Cory Booker actually leads both Warren and Sanders.”

The Lid: I know you are, but what am I?

Don’t miss the pod from yesterday, when we looked at new polling that shows where Americans lay the blame for political polarization.

ICYMI: News clips you shouldn’t miss

New phone records showing Rudy Giuliani’s frequent contact with the White House have security experts worried that foreign intelligence services may be listening in to the president’s calls.

Administration officials are questioning the accuracy of some of those call logs.

The New York Times digs into Buttigieg’s time at McKinsey.

John Kerry endorsed Biden yesterday.

Trump Agenda: No other choice

Nancy Pelosi says the president left Democrats “no choice but to act” on impeachment.

Republican Sen. Kevin Cramer is blocking a resolution on an Armenian genocide measure for now — at the White House’s request.

Another House Republican is calling it quits.

2020: Joe versus the farmer

Here’s Mike Memoli’s full look at Joe Biden’s heated exchange with an Iowa farmer yesterday.

The Washington Post looks at how Democratic senators who are running for president are up against a big impeachment scheduling question.

Cory Booker is making a new diversity push on the campaign trail.

The House Ethics Committee says Duncan Hunter shouldn’t vote on the House floor after his guilty plea.

Democrats are still trying to get Steve Bullock to run for Senate.

Michael Bloomberg is out with a big new gun control plan.