'Start Here': Mueller's docs sought, Trump's taxes requested, Biden's response voiced

Here's what you need to know to start your day.

It's Thursday, April 4, 2019. Let's start here.

1. Hold the subpoenas

The House Judiciary Committee voted along party lines to authorize subpoenas for special counsel Robert Mueller's full, unredacted report and the underlying materials, but Democrats aren't rushing to issue them quite yet.

House Judiciary Committee Chairman Jerry Nadler, D-N.Y., said Wednesday that Attorney General William Barr is being given "time to change his mind" and surrender the report voluntarily, a move ABC News Senior Congressional Correspondent Mary Bruce says is all about building leverage.

"They're essentially making the case," Bruce says on today's podcast, "that they're doing everything they can to get this document, to get this original report and all of the underlying evidence, and that they're giving the attorney general room to play ball with them."

2. A taxing proposition

House Democrats on Wednesday also filed a formal request to see President Donald Trump's tax returns from the last six years.

Trump said he's "not inclined" to comply, citing an ongoing audit, his same response since becoming a candidate. The Internal Revenue Service has yet to confirm or deny whether Trump's actually being audited.

"This is just the opening shot in what's expected on both sides to be a really fierce legal battle that could make its way to the Supreme Court," ABC News' Benjamin Siegel tells "Start Here."

3. 'That's my responsibility'

After four women came forward with claims he acted inappropriately, former Vice President Joe Biden acknowledged in a video message that some of his behavior has made people uncomfortable.

"Social norms are changing," he said. "I understand that, and I've heard what these women are saying. Politics, to me, has always been about making connections, but I will be more mindful about respecting personal space in the future. That's my responsibility, and I will meet it."

Biden stopped short of apologizing to the women, ABC News Deputy Political Director MaryAlice Parks notes on "Start Here." House Speaker Nancy Pelosi has suggested he should, but some Democrats don't believe he needs to.

"There are people coming to his defense -- others are saying he's just too old and can't get it," Parks says. "The Democratic Party is not operating like a monolithic block, and the Democratic Party voters are not going to all agree on this."

4. Who watches the watchers?

Amid widespread outcry over fake news and hate speech, Facebook CEO Mark Zuckerberg says the social media giant is going to create an independent, 40-person oversight board to decide on acceptable content.

The board will have a "judicial structure" and contain individuals who are "free speech and safety experts," Zuckerberg tells ABC News Chief Anchor George Stephanopoulos.

"If we take something down that you think is valid expression, you're gonna be able to appeal that to this oversight board," Zuckerberg says. "And they're gonna have the binding authority to make a decision."

5. Bad data

The fatal crash of Ethiopian Airlines Flight 302 was triggered by a sensor damaged after takeoff, sources familiar with the investigation tell ABC News.

Bad data caused the anti-stall system, or MCAS, to engage, which nosed down the Boeing 737 Max, and the pilots did not try to "trim the plane," or electronically pull the nose of the plane up, before following emergency procedures, the sources say.

While debate continues over whether to blame a lack of pilot training or a design flaw for the crash that killed all 157 people aboard, Senior Transportation Correspondent David Kerley tells us it could have been both.

"Boeing has maintained that there was nothing wrong with the design," Kerley says on "Start Here," "but the software fix changes it fairly dramatically."

Ethiopian Transport Minister Dagmawit Moges said at a press conference earlier today the flight crew followed all recommended procedures but couldn't regain control of the plane.

"Start Here," ABC News' flagship podcast, offers a straightforward look at the day's top stories in 20 minutes. Listen for free every weekday on Apple Podcasts, Google Podcasts, iHeartRadio, Spotify, Stitcher, TuneIn or the ABC News app. Follow @StartHereABC on Twitter, Facebook and Instagram for exclusive content and show updates.

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'First of all, I am the evidence': Tuesday's rant against wind turbines was not Trump's first.

'Plenty of evidence': Preet Bharara, former U.S. Attorney for the Southern District of New York, says on the "Powerhouse Politics" podcast that "Bob Mueller only made a decision about whether or not there was enough evidence to make a criminal case of conspiracy" and that "there is plenty of evidence" to support California Democrat Adam Schiff's inquiries into possible collusion.

'The Trump Administration has undermined key health benefits for our children -- standards for salt and whole grains in school meals -- with deliberate disregard for science, expert opinion, and the law': Six states and Washington, D.C., are suing over declining school lunch standards.

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Doff your cap:

Samiel Asghedom, the older brother of slain rapper Nipsey Hussle, reflects on not only his own personal loss but on the community's staggering loss when his brother was gunned down.

"He was a brother, a musician, an entrepreneur, a people's champ," Asghedom tells ABC News. "He was somebody that believed in the process of hard work, determination and just the positivity of somebody staying in the area that he grew up in and making something out of nothing."