SHANGHAI—Bill Clinton called it a “hundred-to-nothing deal for America.”

U.S. advocates of China’s entry to the World Trade Organization in 2001 saw no downside—“Zero. Zip. Nothing. Nada,” exclaimed the Business Coalition for U.S.-China Trade. After all, China would have to tear down its barriers to trade, while American markets were already wide open.

In a 2010 testimony to Congress, Robert Lighthizer, then a trade lawyer, outlined the loss of U.S. jobs, factories and intellectual property that ensued, along with exploding trade deficits, concluding that the optimists had been “simply wrong” and advocating “a significantly more aggressive approach.” Now, as the Trump administration’s chief trade negotiator, he is readying a barrage of punitive measures. Much of the U.S. political establishment, including both Republicans and Democrats, are cheering him on.

Will Mr. Lighthizer spark a trade war with China and blow up the WTO in the process?

This month’s U.S.-China summit saw the first signs of his strategy at work, with a departure from the old negotiations-based playbook.