For months, United States Steel argued that selling out to Japanese-owned Nippon Steel was the only way to survive. President Joe Biden thought different, concluding that even a takeover by a company based in close ally Japan wasn’t enough to allay national-security concerns.

Such is the new politics of global trade and investment.

In blocking the deal Friday, Biden pointed to what he said was "credible evidence” that Nippon Steel’s $14.1 billion bid would "create risk for our national security and our critical supply chains.” He didn’t say what the evidence was, though he invoked the Defense Production Act, which gives the president power over the economy to ensure the supply of critical goods.