The premise of Donald Trump’s trade war is that other countries should face tariff rates commensurate to the extent of their “cheating” in global trade. Trump insists that this extends well beyond tariffs, which are already zero or near-zero for most goods traded between the U.S. and its major trading partners.

This is not a good way to make trade policy. It effectively cedes U.S. sovereignty over its tariff rates to the decisions made by other countries, and it’s based on the fiction that foreigners pay tariffs. Instead, tariffs are effectively a tax on American consumers. Other countries’ making decisions that the U.S. government doesn’t like is a poor reason to raise taxes on Americans.

But even if the premise of the idea was sound, its implementation is impossible. There are simply too many countries, goods, and factors to consider to ever set rates that would accurately account for what other countries do.