Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings.

DES MOINES, Iowa — No one has more at stake tonight than Joe Biden.

A first-place finish in the Iowa caucuses here could put him the driver’s seat to win the Democratic nomination; a fourth-place finish could end his political career.

No other Top 4 Democrat has that wide range of possibilities.

Pete Buttigieg admitted on “Meet the Press” yesterday that he needs a strong showing to vault him to the later states, but finishing fourth wouldn’t end his political career (he’s just 38 years old).

Bernie Sanders and Elizabeth Warren could very well win tonight, but that wouldn’t put them in the driver’s seat for the nomination — at least not yet.

And while Warren really can’t afford to finish behind Biden and Sanders, both of the progressive senators have the money to sustain a worse-than-expected showing.

When he was trying to convince Biden not to run for president in 2015-2016, former top Obama adviser David Plouffe reportedly told the former vice president: “Do you really want [your career] to end in a hotel room in Des Moines, coming in third to Bernie Sanders?”

Well, Biden’s back in Des Moines.

Does he come in third (or worse) to Bernie Sanders?

Or does he finish first — which is doable if a “Stop Bernie” effort coalesces around him in the caucus realignment process? (More on that process below.)

We’ll find out later tonight.

Answering the E-word

The reason that Biden has so much at stake tonight is that he’s branded himself as the most “electable” Democrat.

But how electable are you if you finish fourth — in Iowa?

Tonight, we’re also going to get our first answer at what “electability” means to Democratic primary voters.

Does it mean the Dem candidate who consistently outperforms the others in national and battleground polls? (If so, that’s Biden; check out our latest NBC News/Wall Street Journal poll.)

Does it mean the candidate who gets the biggest crowds and support from young voters? (That’s Sanders.)

Does it mean the candidate who might have the best ability to unite the Bernie-versus-Biden factions? (That’s Warren.)

Does it mean the candidate who’s the freshest face and the biggest Washington outsider? (That’s Buttigieg.)

Or does it mean anyone who can’t legitimately be labeled a socialist? (Once again, check out our NBC/WSJ poll on capitalism versus socialism.)

Iowa voters, what say you?

We have two more questions:

Are there really only two tickets out of Iowa — with Michael Bloomberg purchasing the third? Think about it: The only realistic third-place finish that would be a positive story for that candidate is Amy Klobuchar’s.

And if Sanders really does win Iowa, does he start acting like a front-runner? How he declares victory, if he wins, will matter.

GOP’s Alexander: Trump won’t try to do it again

Turning to the impeachment story, the Senate is on the verge of acquitting President Trump on Wednesday — after enough GOP senators voted not to hear from witnesses.

One of those senators was Sen. Lamar Alexander, R-Tenn., who argued that, yes, Trump did ask Ukraine to investigate the Bidens — but that he doesn’t deserve impeachment over it.

That decision, Alexander said, should be up to the voters in the next election.

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

But as we asked on Friday: What’s to stop Trump from doing it again?

Well, Alexander got to answer that question on “Meet the Press.”

Chuck Todd: "Are you at all concerned, though, when you seek foreign interference, he does not believe he's done anything wrong, that what has happened here might encourage him that he can continue to do this?"

Alexander: "I don't think so. I hope not. I mean, enduring an impeachment is something that nobody should like. Even the president said he didn't want that on his resume. I don't blame him. So, if a call like that gets you an impeachment, I would think he would think twice before he did it again."

Todd: "What example in the life of Donald Trump has he been chastened?"

Alexander: "I haven't studied his life that close. But, like most people who survive to make it to the presidency, he's sure of himself. But hopefully, he'll look at this and say, 'Okay, that was a mistake. I shouldn't have done that, shouldn't have done it that way.' And he'll focus on the strengths of his administration, which are considerable."

Meanwhile, after Trump’s lawyers argued that impeachment has become too commonplace and weaponized in our politics, Sen. Joni Ernst, R-Iowa, warned that Biden could be impeached over Ukraine and Burisma if he wins the White House.

2020 Vision: Everything you wanted to know about the caucuses (but were afraid to ask)

The individual 1,679 caucus sites in Iowa close at 8:00 p.m. ET (7:00 p.m. CT).

Unlike primary contests, caucuses work with Democrats moving around the event site — Joe Biden supporters, for instance, gathering in one corner of a gymnasium; Bernie Sanders and Elizabeth Warren backers in another.

At most locations, a candidate must get support from at least 15 percent of attendees to achieve viability. If that threshold isn’t met, a candidate’s supporters must realign to a different viable candidate or join with other non-viable groups to form a viable one.

In a change from past Democratic caucuses, the party will release three different sets of results: 1) “first expression of preference” before the realignment; 2) “final expression of preference” after the realignment; and 3) State Delegate Equivalents (the number used to determine the “winner” in past Iowa caucuses.

All of the numbers will be released at the same time.

Bottom line: The first two numbers are a transparent way to describe how you arrive at the third number that determines the winner.

On the campaign trail today

In Iowa, the candidates and their surrogates hold multiple canvass kickoffs throughout the state… Elsewhere, Michael Bloomberg stumps in Fresno, Calif… And Deval Patrick is in New Hampshire.

Dispatches from NBC’s campaign embeds: On the eve of the Iowa caucuses, the candidates made their final pitches to Iowans yesterday:

NBC’s Marianna Sotomayor on Joe Biden’s final message: Biden’s rally cry centered on five points — “Democracy begins in Iowa”, “Charlottesville as the pivotal moment”, “the need to unite the country”, “refuse to believe” America is the country President Trump has made it, and “hope over fear.”

Per NBC’s Gary Grumbach, Bernie Sanders said he was looking forward to victory: “Sanders held his final canvass launch of the Iowa Caucus this afternoon in Newton, IA, said, ‘I want to thank all of my volunteers and staff,” Sanders said. ‘Tonight I’m getting on a plane back to Washington. Tomorrow I’m coming back to Iowa, and I’m looking forward to a victory tomorrow night.’”

For Warren, women win, NBC’s Deepa Shivaram reports: “Right now across in America in competitive races, women are outperforming men,” Warren said. “So here' how I see this – our number one job is to beat Donald Trump. Women win.”

Tweet of the day

This tweet comes amid an ongoing news cycle where Trump’s Secretary of State — who is very prominently from Kansas — claimed a reporter couldn’t find something on a map pic.twitter.com/0ipt6MCaWi — Allan Smith (@akarl_smith) February 3, 2020

Data Download: The number of the day is … 47 percent

47 percent.

That’s the share of registered voters who agree with the statement “we need to keep shaking things up and make major changes in the way the government operates,” according to the latest NBC/WSJ survey release.

Forty-five percent choose the statement “we need more competence and a steady approach” instead.

Among Republicans, a majority — 59 percent — choose the “shake things up” option, while just 33 percent prefer a “steady” approach to government.

But among Democrats, it’s almost a mirror image, with about six-in-10 saying competence is their top choice.

The Lid: The Io-way

Don’t miss the pod from Friday, when two of us went through a variety of caucus scenarios in a special edition of The Lid.

ICYMI: News clips you shouldn’t miss

Here are the key counties to watch tonight in Iowa.

And NBC’s Benjy Sarlin looks at the five policy fights that have defined the Dem race.

Elizabeth Warren is talking a lot about “unity” in her closing argument. There’s a mathematical reason why.

Pete Buttigieg hopes a rural focus on Iowa pays off in the delegate count.

New Hampshire voters feel a little left out this cycle — particularly because of impeachment.

Our latest NBC/WSJ poll shows just how divided Americans still are over the Senate trial.

POLITICO notes that: “Whoever wins Iowa, they won’t be back” in a state that’s trending red.

Trump Agenda: The impeachment trial continues

The impeachment trial continues in the Senate today.

Newly released emails from NOAA show the uproar over SharpieGate.

The law firm representing Rudy Giuliani is beset with a scandal and high-stakes legal battle.

2020: “Trench warfare”

Some Iowans think the future will be all about “trench warfare.”

And many in the state are worried about choosing wrong in a high-stakes caucus.

In case you missed it, Trump and Bloomberg got into a war of insults on Twitter over the weekend.

The New York Times checks in with Joe Walsh.