Trade Policy Built on Perpetual Confusion Won’t Work: Editorial

Recurring legal setbacks haven’t deflected the White House from its plan to impose a worldwide tariff regime. Whether the fourth variant of this protectionist strategy, proposed last week, will fare better in the courts than its predecessors is doubtful. What’s certain is that it will cause yet more disruption, compound the economic damage already done and further harm US relations with its allies.

To recap, the Supreme Court invalidated the administration’s “Liberation Day” tariffs in February, ruling that they misapplied federal law. Last month, the US Court of International Trade ruled that the next iteration, so-called Section 122 tariffs set ...