'Start Here': House prepares to vote on impeachment and Boeing to suspend 737 Max production

It's Tuesday, Dec. 17, 2019. Let's start here.

1. Impeachment poll

As the House is expected to vote tomorrow on whether to impeach President Donald Trump, a new ABC News/Washington Post poll has found the country is divided on the topic with 49 percent in favor and 46 percent opposed.

Seven in 10 Americans also say the president should allow his top aides to testify in a Senate trial on the impeachment charges against him, but according to ABC News' Trish Turner on "Start Here" today, it's still unclear whether that trial will include any witnesses at all.

"It's really hard to say what's going to happen here... but what's really happening behind the scenes, as we understand from our reporting, is that the White House is warming to the idea of a short trial with few, if any, witnesses," she says.

2. Boeing halts production

Boeing has announced it will suspend production of its 737 MAX jets in the wake of two deadly crashes.

"It is unprecedented," ABC News Senior Transportation Correspondent David Kerley tells the podcast. "Never before have we seen Boeing shut down a line when the entire fleet of the aircraft it is manufacturing is grounded."

The company said no layoffs or furloughs are expected because of the decision, but thousands of workers could be re-assigned or work on keeping the stored aircraft preserved.

3. On or off?

Democratic presidential candidates are threatening to boycott Thursday's debate in Los Angeles over a labor dispute as they vow not to "cross a picket line."

"This was a bold, brazen move by the union to threaten picketing right there in front of the debate, but it played into Democratic priorities," ABC News Deputy Political Director MaryAlice Parks says.

4. Homeless ruling

The Supreme Court has decided to leave in place a lower court ruling that barred criminal prosecution for homeless people living in the streets.

ABC News Chief National Correspondent Matt Gutman breaks down the ruling's impact on Los Angeles and other cities that are trying to address growing homeless populations.

"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.

Elsewhere:

'Bent on supporting ISIS': A Connecticut man was arrested over the weekend as he prepared to flee the U.S. to join ISIS, federal authorities said.

'Endangered': Authorities are desperately searching for two young children who disappeared over the weekend in Jacksonville, Florida.

'She fought to live': As politicians and local leaders gathered in Manhattan's Morningside Park Sunday to grieve the college first-year who was stabbed to death there, they vowed to honor the young woman's life and return safety to the local park.

'Angry and shaken': Jewelry believed to be worth tens of millions of dollars has been stolen from the house of British billionaire heiress Tamara Ecclestone in London after she left the home for the Christmas holidays.

From our friends at FiveThirtyEight:

'Why the Democrats have shifted left over the last 30 years': Senators Elizabeth Warren and Bernie Sanders still sit atop the national polls. Is this apparent leftward shift in the Democratic Party real? And if so, what’s driving it?

Doff your cap:

Two "Schitt's Creek" fans went to the Rose Apothecary pop-up and left with more than a novelty souvenir or ironic t-shirt.

The network behind the hit Canadian TV show, Pop TV, shared a photo of John Calado who was down on one knee in front of his partner, Jonathan Chiaramonte, at the New York City storefront.

"HE SAID YES," Calado wrote in the comments on Instagram with three heart emojis.