Set to take effect Aug. 1, the tariff is apparently a method for leverage in trade negotiations with Canada, Mexico and Chile, the world's leader in copper production.

Copper is heavily used in industry and defense and the tariff will allow the U.S. to rebuild the domestic industry into one that is "dominant," Trump said on Truth Social. "America cannot be reliant on foreign imports of the copper that's necessary for key military hardware, infrastructure and everyday electronics," a White House spokesman said in a statement to CBS MoneyWatch.

ING, the banking and finance company, said only 5% of the world's copper is produced in the U.S., down substantially in the last decade. Building new mines in the U.S. involves lengthy permitting that lasts decades, according to ING.

Copper commodity trading futures reached record highs on the day of the announcement. The tariff plan was not a complete surprise although the size of it was unexpected. The Trump administration claimed it had been studying the matter for months.

The National Electrical Contractors Association said it has been fighting against the tariff all year and "has been successful in keeping it off the table until now." It added: "We’ve made our case directly to policymakers in both Congress and the administration, warning that raising copper tariffs will strain supply chains, inflate project costs and slow down the very infrastructure and energy deployment goals the nation is trying to achieve. We are not done fighting."