'Start Here': Trump escalates trade war with China, Biden 'surprised' by attacks on Obama

It's Friday, Aug. 2, 2019. Let's start here.

1. Tariff threat

President Donald Trump escalated the trade war with China on Thursday, announcing he would impose a 10% tariff on $300 billion of Chinese goods starting Sept. 1.

"If they don't want to trade with us anymore, that would be fine with me," Trump told reporters before departing for a campaign rally. "We'd save a lot of money."

But American companies and consumers could take a massive hit, ABC News Senior Washington Reporter Devin Dwyer tells "Start Here."

"Products are going to get a lot more expensive, businesses are going to have to pay more for those imports," Dwyer says. "We've been here so many times before where he issues these threats and then he backs off. We'll see if he can extract anything out of this round of threats or whether we actually are headed for another round of tariffs in just 30 days."

2. No thanks, Obama

A new Democratic strategy emerged in this week's primary debates: going after former President Barack Obama's legacy.

Front-runner and former Vice President Joe Biden said Thursday it was "bizarre" other Democratic presidential hopefuls focused attacks on Obama's immigration and health care policies, adding, "I don't think there's anything that he has to apologize for. It kind of surprised me, the degree of the criticism."

Democrats may be moving to the left, but because Obama remains very popular in the party, candidates should be wary of criticizing his record, says ABC News Chief Political Analyst Matthew Dowd: "Going on the attack on Obama policies, or the Obama presidency, or things they didn't like, is completely the wrong tact to take among Democratic voters, and then lead that into swing voters."

3. UnSEALed

"We have a problem," Rear Adm. Collin Green, the top U.S. Navy SEAL, reportedly wrote to commanders in a recent letter obtained by CNN.

Green was addressing troubling headlines affecting the SEAL community, including the SEAL Team 7 platoon that was sent home from Iraq after drinking during its deployment and an alleged sexual assault by one member. There also was an internal report obtained by the Navy Times that found some members of SEAL Team 10 allegedly used cocaine, but passed drug tests when they were stationed in Virginia.

Military officials have stopped short of calling the incidents a cultural issue, but they are acknowledging that there is a problem, according to ABC News' Elizabeth McLaughlin: "I think it's finally becoming more talked about and not as dismissed."

When Navy Vice Adm. Michael Gilday, confirmed as chief of naval operations by the Senate on Thursday, was questioned by lawmakers about the misconduct during his confirmation hearing, he said he would commit to "getting after the root causes and ensure if there is a problem with the culture of the community, that that is addressed ... very quickly and very firmly."

4. Alexa, what are 'HIPAA restrictions'?

Amazon recently announced six new "healthcare skills" for its Alexa-enabled devices, allowing the voice assistant access to patient information with participating health care companies, while also remaining compliant with the Health Insurance Portability and Accountability Act of 1996.

But Amazon's foray into health care has raised privacy concerns: If Alexa knows about users' diagnoses and prescriptions, could it share that health information with Amazon?

Although Amazon can't store or manipulate the data under HIPAA restrictions, according to Kaiser Health News' Janet Rae-Dupree, there are always privacy questions with any emerging tech: "It is absolutely to be expected that you cannot guarantee security in any technology."

Amazon did not immediately respond to ABC News' request for comment, but has said that it has safeguards to protect information required under HIPAA for its eligible services.

"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:

'This is just people behaving badly': A man is arrested at an Elizabeth Warren event in Arizona after getting into a dispute with Donald Trump supporters.

'An ongoing investigation': A woman dies after being shot by a cop who was firing his gun at a dog.

'He's so thankful for me, and I'm thankful for him': The story behind the collaboration that led to "Old Town Road."

From our friends at FiveThirtyEight:

Sage Rosenfels was the Tom Brady of the NFL Preseason: No, really.

Doff your cap:

It was hot day in June 2017 when Erin Holley and her family were in the midst of moving to another home.

Holley, her husband and two children, who were 4 years old and 4 weeks old at the time, were riding in two separate cars to a storage facility. The couple decided to take a break, jump into one car and bring the kids to the park.

"We drove to the park and when we went to move the bucket car seat to the stroller, we realized he was not in the car," she said. "I couldn’t feel my extremities, and I screamed, 'Oh my God, the baby.'"

The parents raced back to Finn, beating paramedics they had called en route. When they arrived, the car was thankfully still cool from the shade. Finn was sleeping peacefully, unaware.

Paramedics checked the child's vitals and all was fine, Holley explained.

At a May press conference in front of the U.S. Capitol in Washington, Holley detailed her frightening close call when her 4-week-old son was forgotten in a hot car. The purpose of the press event was to promote the Hot Cars Act, which is a bill introduced in 2017 with the support of the Kids and Cars organization.

Holley is now committed to spreading awareness on hot-car accidents, as a parent advocate for Kids and Cars.

"But that was when I realized this can happen to anyone," Holley said at the Capitol. "If you had offered me, prior to that day, optional technology (in a car seat for example) to prevent it, I would have emphatically declined and told you I was incapable of leaving my baby in a hot car. I am a cautious, loving, aware mother of two."