Tariffs are taxes, which distort investment and limit growth. And like taxes, when tariffs are high they create a political incentive for exemptions and favoritism. Behold the Commerce Department’s new and tortuous process for reviewing exemptions to steel and aluminum tariffs. This is everything Republicans typically claim to hate.

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First, companies must submit a request attesting that their imports aren’t made in the U.S. in “a satisfactory quality” or “sufficient and reasonably available amount.” Companies must state...