Having lost patience with China, the Trump administration is studying new steps to starve North Korea of cash for its nuclear program.
The options include one that would infuriate Beijing: sanctions on Chinese companies that help keep the North's economy afloat.
It's an approach that's paid off for the U.S. in the past, including with Iran. So-called secondary sanctions upped the economic pressure on Tehran and helped drive it to the nuclear negotiating table.
There are significant risks, too, however. They include opening a new rift with Beijing that could complicate other U.S. diplomatic efforts.
Washington already has sanctions on North Korean companies and people accused of illicit dealings with the North. Secondary sanctions would target banks and companies that do legitimate business with North Korea.