WASHINGTON — The political scandal of 2016 was the Trump campaign gladly accepting assistance from Russia’s interference in the election to hurt Hillary Clinton’s candidacy.

Is the political scandal of 2019 — one day after Robert Mueller’s July 24 testimony on Capitol Hill — President Trump’s phone conversation with Ukraine’s new president, in which Trump allegedly tied together foreign aid and investigating Joe Biden’s family?

Here’s what we do know:

Last May, we learned from the New York Times that Trump lawyer Rudy Giuliani had been pressing Ukraine to investigate, among other things, the involvement of Joe Biden’s son in a gas company owned by a Ukrainian oligarch.

Trump spoke with Ukrainian President Volodymyr Zelensky on July 25.

Two and a half weeks later, a whistleblower filed a complaint about a phone conversation the president had with a foreign leader — troubled by a promise Trump had made.

The Washington Post reported that the whistleblower complaint centered on Ukraine. (NBC News has not been able to confirm that.)

Sen. Chris Murphy, D-Conn., tweeted last night that he met with Zelensky in Ukraine a few weeks ago, and Zelensky was concerned about the cut-off of U.S. aid to Ukraine.

On CNN last night, Giuliani first denied he asked Ukraine to investigate Biden and his family. Then he admitted it.

Then Giuliani tweeted that Trump was only doing his job in asking Ukraine to investigate corruption affecting the United States. (“A President telling a Pres-elect of a well known corrupt country he better investigate corruption that affects US is doing his job. Maybe if Obama did that the Biden Family wouldn’t have bilked millions from Ukraine and billions from China; being covered up by a Corrupt Media,” Giuliani said.)

Here's what we don't know:

What was the actual substance of Trump’s call with Zelensky?

Is there a transcript or recording of it?

Will we ever see a transcript or hear a recording?

If this is what this looks like — and again, we don’t know the actual substance of the July 25 call — then it’s arguably worse than Watergate, when the dirty tricks were being conducted by Americans against Americans.

But this time, is the dirty trick a sitting president dangling aid to a foreign country to get it to investigate a rival campaign?

We learned from 2016 that the Trump campaign will do whatever it takes to win.

Do national Democrats — who believe defeating Trump in 2020, not impeaching him, is the best way to remove him from office — understand what else we might see over the next 14 months?

Trump will speak to the press today

At 11:45 a.m. ET from the White House, President Trump will have a joint press availability with Australia’s prime minister.

So Trump will get asked about this whistleblower-Ukraine story.

For Harris, it’s Iowa or bust

“Kamala Harris’ presidential campaign announced on Thursday a doubling of staff in Iowa and a commitment that the candidate would spend ‘about half of October’ in the state to ensure the California senator finishes in the top-three on caucus night next February,” per NBC’s Vaughn Hillyard and Deepa Shivaram.

“We want to make sure that we have a strong top-three finish,” Juan Rodriguez, Harris’ campaign manager, said on a call with reporters. “I think that will kind of continue to give us a slingshot to go into that early primary state calendar and then make sure that we’re also competitive heading into Super Tuesday.”

Tweet of the day

Breaking: Bill de Blasio announces he is ending his presidential campaign pic.twitter.com/vL8GcX3xV5 — Morning Joe (@Morning_Joe) September 20, 2019

2020 Vision: Fried up, ready to go

Democratic presidential hopefuls will once again descend upon Iowa this weekend, this time for the Polk County Democrats Steak Fry, per NBC’s Priscilla Thompson and Maura Barrett.

This year’s big event falls on the first day of autumn, which also signifies the point when campaigns ramp up their efforts aimed at winning the Iowa caucuses in February. The fundraiser will feature 18 candidates (!!!) and is expected to draw more than 11,000 people to Des Moines on Saturday. The audience will be made up of mostly Iowans, but the Polk County Democrats tell NBC News there’s been a significant uptick in out of state ticket sales this year with folks buying tickets from 48 different states.

Held at Water Works Park, a 1,500 acre green space, the event is yet another opportunity for campaigns to turn out their supporters and volunteers in massive numbers to demonstrate strong organization and excitement around their candidate, Thompson and Barrett add.

On the campaign trail today

Ahead of Saturday’s Steak Fry, it’s a big day in Iowa, with Joe Biden, Elizabeth Warren, Kamala Harris, Amy Klobuchar, Cory Booker and others participating in a LGBTQ forum in Cedar Rapids… Biden holds a climate-change town hall in Cedar Rapids before that… Booker, Pete Buttigieg, Steve Bullock and others take part in the second day of the MSNBC climate forum at Georgetown University in DC… Bernie Sanders stumps in North Carolina and South Carolina… Beto O’Rourke talks reducing gun violence in Colorado… And Mark Sanford is in New Hampshire.

Dispatches from NBC’s embeds

Bernie Sanders kicked off a “college tour” swing last night at the University of North Carolina, where he touted his campaign hitting one million individual donors. NBC’s Gary Grumbach reports Sanders’ comments, “I would contrast that with how my good friend Vice President Biden is raising money today. And I would say to him, Joe, we are not going to make the changes needed in this country when you go to three fundraisers in Chicago sponsored by multi-millionaires.”

Data Download: The number of the day is … 81 percent

81 percent.

That’s the share of U.S. adults who say members of Congress behave unethically all (17 percent) or most (64 percent) of the time, according to a new survey from the Pew Research Center.

The Lid: I’m LeBron, baby

Don’t miss the pod from yesterday, when we looked at how Barack Obama still enjoys sky-high ratings from Democratic primary voters.

ICYMI: News clips you shouldn’t miss

Here’s everything our team is reporting on the spiraling controversy around that whistleblower complaint.

The Pentagon is fighting back against the administration’s efforts to slash the number of refugees allowed in the U.S.

The Trump administration ignored evidence from Customs and Border Protection that pointed to the effects of climate change as a key driver of migration from Central America.

Three recent failed House candidates are running for Senate in 2020. NBC’s Jacob Rubashkin looks at how that’s worked out for previous hopefuls.

Trump Agenda: The Social Network

Trump met with Mark Zuckerberg yesterday at the White House.

Mitch McConnell is changing course and backing $250 million for election security.

Officials are considering diverting even more money from military funding to pay for wall construction.

Ben Carson is in hot water after comments he made about transgender people.

2020: Buttigieg vs. Warren

Buttigieg is taking the gloves off when it comes to attacks on rival Elizabeth Warren.

Cory Booker used to be a fan of school choice — and was even allied with Betsy DeVos.

Young black voters are telling their parents that they’re over Joe Biden, the New York Times writes.

And young voters aren’t just all-in on Bernie Sanders this cycle.

Pete Buttigieg has hired a black outreach director.

This Darrell Issa background check-or-Congressional-run story is getting interesting.