Teachers and students hold signs as they protest during a one-day strike outside of Oakland High School in 2010 in Oakland, California. Photo: Justin Sullivan/Getty Images

Teachers in Oakland began a strike Thursday morning, joining Los Angeles and Denver among major U.S. cities that have seen teachers' strikes in recent months, reports the East Bay Times.

The big picture: The teachers are demanding a 12% raise over the next 3 years, citing the Bay Area's sky-high cost of living, and rejected Oakland Unified School District's last offer of an 8.5% raise over 4 years. The district argues that it simply can't meet the teachers' salary demand as it already faces a budget shortfall of more than $50 million by the 2020-2021 school year.

Go deeper: No end in sight for nationwide wave of teacher strikes

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There's little consensus on TikTok's specific national security threat

Illustration: Aïda Amer/Axios

TikTok has become a Rorschach test for how U.S. politicians view China, with little consensus on the specifics of its threat to homeland security.

The big picture: Much of what D.C. fears about TikTok is fear itself, and that's reflected in President Trump's executive order to ban the app by Sept. 20 if it's not sold by parent company ByteDance — alongside another focused on Chinese messaging app WeChat and its parent company Tencent.

U.S. sanctions Hong Kong leader Carrie Lam

Photo: Anthony Kwan/Getty Images)

The Treasury Department on Friday placed sanctions on Hong Kong leader Carrie Lam, following months of tension as she has allowed continued overreach by Beijing to subvert Hong Kong's autonomy.

Why it matters: It's the toughest sanction yet imposed on China for its destruction of Hong Kong’s relatively free political system.

GM's high-stakes electric move

The Cadillac Lyriq. Image courtesy of Cadillac

Cadillac on Thursday unveiled the Lyriq, the luxury brand's first all-electric model and GM's first consumer electric vehicle unveil since the Chevy Bolt several years ago.

Why it matters: It's the first reveal by GM of an electric vehicle that will use the company's new modular platform and Ultium battery system — technologies meant to underpin the 20 electric vehicles that GM plans to launch by 2023.