That changed in 2017, with a claim by Russia, which had imposed myriad trade and transit restrictions on Ukraine, which challenged the Russian measures at the W.T.O. In the dispute, Russia contends that the moment any country claims its actions are based on national security, the judges hearing the case must put down their pens and go home. The only W.T.O. member joining Russia’s contention is the United States.

This is dangerous. It provides all countries with a “get out of jail free” card that can be played just by saying the magic words “national security.”

Blurring the line between economic and national security also invites retaliation. The United States agreed to eliminate steel tariffs and lower aluminum tariffs to below 5 percent in 1995 in exchange for tariff cuts by others. Now, by imposing 25 percent tariffs on steel and 10 percent on aluminum, the United States has broken that commitment. And by imposing the tariffs on some but not all trading partners (South Korea, Australia, Argentina and Brazil are exempt), the United States has also broken its commitment not to discriminate among W.T.O. members.

Already our partners are reacting. China has placed tariffs on American exports of nuts, fruits, wine, pork and some steel pipes. Canada, the European Union, Mexico, Japan, India, Turkey and Russia may impose their own retaliatory tariffs. This adds tremendous chaos to the trading system and may signal the start of a global trade war.

Moreover, the Trump administration is sacrificing real national security concerns for short-term economic gains. How else to describe a decision to dispose of the Commerce Department’s settlement with ZTE? It followed a multiyear investigation finding 380 alleged and admitted violations of American law by the Chinese telecomm giant. These included conspiracies, false statements and deceptions to obtain contracts to supply, build, and operate telecommunications networks in Iran, and to illegally ship telecommunications equipment to North Korea.

If we impose tariffs on steel and cars based on a claim that those imports threaten our national security, what will we do if and when our national security is really threatened? Auto production in the United States has more than doubled since 2009, and imports of Chinese steel have fallen by nearly 75 percent since their 2014 peak. Why attack imports from longstanding allies now? Especially when it does nothing to target China’s massive subsidies, intellectual property theft, and unfair takeovers of technology — actions that truly threaten our national security.

Erasing the line dividing national security from economic security threatens both. Congress needs to recognize the danger and limit the president’s authority to raise the specter of national security at every turn. At the same time, Congress must ensure that genuine concerns are not traded away for limited economic gains. Cavalier use of rarely invoked laws will only undermine their purpose and put the trading system at risk.