President Trump has authorized Commerce Secretary Wilbur Ross to investigate U.S. imports on a national security basis.
The details: The investigations will be implemented under the 1962 Trade Expansion Act — a decades-old law that could impose penalties on improper imports, specifically steel, from certain countries, specifically China. These import penalties have not been invoked since 1992, when the World Trade Organization was founded.
Why this matters: It's a significant step toward Trump's "America First" policy. China's overproduction of steel is also an issue for the economy, and imposing penalties on their imports could strain the US-China relationship, especially if done for the first time since 1992 and when Trump has relied on them for help with North Korea.