WASHINGTON — Yesterday brought us the most clarifying moment of this entire Ukraine-Trump-whistleblower story.

In a news conference, President Trump refused — repeatedly — to answer a simple question about what he wanted Ukraine President Zelensky to do regarding Joe Biden and his son, Hunter:

Question: "What about Mr. Biden? What did you want about Biden? What did you want him to look into about Biden?"

Trump: "Look, Biden and his son are stone cold crooked, and you know it. His son walks out with millions of dollars. The kid knows nothing. You know it, and so do we. Go ahead ask a question."

Question: "The question, sir, was what did you want President Zelensky to do about Vice President Biden and his son, Hunter?"

Trump: "Are you talking to me?"

Question: "Yeah, it was just a follow-up of what I just asked you, sir."

Trump: "Listen. You ready? We have the president of Finland. Ask him a question."

Question: "I have one for him. I just wanted to follow up on the one that I asked you, which was what did you want ..."

Trump: "Did you hear me? Did you hear me? Ask him a question, please. I've given you a long answer. Ask this gentleman a question. Don't be rude."

Question: "No, Sir. I don't want to be rude. I just wanted you to have a chance to answer the question that I asked you."

Trump: "I answered everything."

But he didn’t answer anything on that question.

If you wanted an “AHA” moment in this story, you got it.

To remind you, here’s what Trump asked Zelensky, according to the transcription memo of that July 25 call.

The other thing, there's a lot of talk about Biden's son, that Biden stopped the prosecution and a lot of people want to find out about that so whatever you can do with the Attorney General [referring to Bill Barr] would be great. Biden went around bragging that he stopped the prosecution so if you can look into it ... It sounds horrible to me.

Trump can’t both claim that everything in that transcription memo is “perfect” and “not a thing wrong with it” and also refuse to answer the most significant allegation arising from that July 25 call.

That he asked another world leader for help against the man who might be his chief rival in the 2020 presidential election.

Biden fires back at Trump

Former Vice President Joe Biden last night delivered his most forceful remarks to date responding to Trump over the Ukraine controversy, per NBC’s Marianna Sotomayor.

“Let me make something clear to Trump and his hatchet men and the special interests funding his attacks against me: I’m not going anywhere. You’re not going to destroy me. And you’re not going to destroy my family.”

Biden added, “I don’t care how much money you spend or how dirty the attacks get.”

The question we have: Why it did it take Biden this long to deliver that response?

Tweet of the day

Two people whom @SecPompeo cannot control - the State IG and Volker who is now a private citizen - will speak with Congress this week. https://t.co/Xirlx9W0QD — Sam Vinograd (@sam_vinograd) October 2, 2019

2020 Vision: We still don’t know a lot about Bernie Sanders’ medical situation

Here are the facts regarding Bernie Sanders’ health situation:

His campaign revealed yesterday that he had an emergency heart procedure on Tuesday night (“he was found to have a blockage in one artery and two stents were successfully inserted,” a statement campaign said).

Sanders tweeted that he’s “feeling good. I'm fortunate to have good health care and great doctors and nurses helping me to recover.”

The campaign has canceled events and appearances until further notice.

And the political world is sending him best wishes for a strong recovery.

But that’s all we know. And the lack of additional information only leads to articles like this from Slate: “Did Bernie Sanders Have a Heart Attack?”

As long as he’s a presidential candidate, at age 78, the campaign owes the public more answers about his health situation.

Just ask yourself how we’d be approaching this story if the candidate was Hillary Clinton, or Donald Trump, or Joe Biden.

On the campaign trail today

Elizabeth Warren holds a town hall in San Diego, Calif…. Kamala Harris and Beto O’Rourke stump in Nevada… Amy Klobuchar campaigns in Iowa… And Tulsi Gabbard is in New Hampshire.

Dispatches from NBC’s embeds

Tulsi Gabbard campaigned in New Hampshire, while most of her Democratic opponents were in Las Vegas at a gun control forum, and said she’d be open to meeting with NRA Chief Executive Wayne LaPierre. NBC’s Julia Jester reports, “A lifetime NRA member suggested a ‘bold move’ that she take a meeting with Wayne LaPierre, arguing, ‘You sat down with Assad, I don’t think Wayne LaPierre is that scary.’” Gabbard responded, “That’s something I’d be open to. And you’re exactly right. Just as with our foreign policy, we have to be willing to meet with leaders and whoever they may be — adversaries or dictators or otherwise — because the only alternative to diplomacy is war. And we have to be willing to do the same right here at home.”

The chairman of the Nevada Republican Party tweeted out a video of supporters of President Trump heckling Elizabeth Warren as she arrived in Reno, Nevada, NBC’s Benjamin Pu flags. The video shows protestors screaming, “stop the impeachment” and calling Warren a Native American slur. The state party chairman Michael McDonald tweeted alongside the video, “Welcome to Reno @ewarren! This is @teamtrump country!!”

Data Download: The number of the day is … $1.3 million

$1.3 million.

That's what Bernie Sanders planned to spend on a TV ad buy in Iowa before abruptly canceling it yesterday.

Sanders announced the major buy on Tuesday but pulled it from stations yesterday morning, according to ad trackers at Advertising Analytics. The campaign described the move as a "postponement."

The Lid: Nothin’ could be finer

Don't miss the pod from yesterday, when we checked in with some early states that aren't Iowa and New Hampshire.

ICYMI: New clips you shouldn’t miss

The Washington Post reports that Trump involved Mike Pence in his efforts to pressure the Ukrainian president.

The State Department's inspector general briefed congressional aides yesterday about apparent attempts to smear the former ambassador to Ukraine.

The president used two interchanges with the media yesterday to turn impeachment into a partisan rallying cry, writes Jonathan Allen.

Trump, Republicans have accused House Intel Chair Schiff of orchestrating the whistleblower complaint.

The Trump administration wants to expand the collection of DNA from migrants in custody and share it with the FBI.

Trump Agenda: So you’re the president of Finland…

The New York Times looks at the challenges faced by foreign leaders visiting the White House.

The president is heading to the warm embrace of The Villages.

Tim Cook filed an amicus brief in support of DACA recipients.

2020: Beto vs. Pete on guns

Beto O'Rourke and Pete Buttigieg got into a back-and-forth on guns.

Joe Biden is working on building a Super Tuesday firewall.

Cory Booker has released a new plan to address child poverty.

Democrats are grumbling about the crowded October debate stage.

Andrew Yang's big fundraising haul is putting other candidates to shame.