President Donald Trump justified the tariffs by citing section 232 of the Trade Expansion Act, a little-known 1962 law that gives the White House wide latitude on trade matters, especially if it is determined that imports threaten national security. Trump has said a healthy steel industry is vital to defense efforts.

“These tariffs will do nothing to uphold their stated purpose of protecting U.S. national security,” said coalition spokesperson Paul Nathanson. “They will instead hurt U.S. manufacturers in the near term by raising the price of the essential inputs they need to make finished products, and do long-term harm to domestic steel producers by eroding their own customer base.”

Every industry that uses either metal is harmed by the levies, Nathanson said.

“It doesn’t matter what finished product you manufacture; if you use steel or aluminum as an input, your costs are rising as a result of these tariffs,” he said. “It also doesn’t matter whether you use domestic or imported steel or aluminum, because the effect is the same: higher prices for your basic inputs.”

The campaign unveiled a website, www.tariffsaretaxes.org, to rally opposition to the tariffs.

“Tariffs help a small handful of steel producers while jeopardizing the viability of thousands of steel-using manufacturers,” he said. “Tariffs are taxes, plain and simple. The administration’s stated goal is to create new jobs and help U.S. manufacturers prosper, but these tariffs will bring the opposite result.”