Steel tariffs (Section 232)

On March 8, 2018, President Trump imposed a 25% tariff on steel imports using Section 232 of the Trade Expansion Act of 1962 — a Cold War-era statute that lets the president restrict imports that threaten national security. The legal hook was a Commerce Department finding that steel imports erode the domestic industrial base the military relies on.

The tariff was global in name but not at first in practice: Canada, Mexico, the EU and a few others were temporarily exempted while the administration tried to negotiate quotas. Those exemptions ended on June 1, 2018, pulling most allies back in. A wave of WTO and federal court challenges followed; none toppled the tariff, and the Supreme Court later let Section 232 stand.

What makes this durable is that Section 232 is a different legal animal from the 2025 IEEPA tariffs that the Supreme Court struck down in February 2026. Section 232 has explicit congressional authorization for trade-restricting national-security action, so this tariff outlived the IEEPA era. The Biden administration kept it; the second Trump administration raised it — on many partners to a straight 25%, and on some steel to 50% in mid-2025.

Translation for normal people: if you make things out of steel in America, this tariff is still adding cost to your inputs today.

Directly: U.S. companies that import steel (steel service centers, manufacturers buying foreign mill output)

Ultimately: Downstream manufacturers (autos, construction, machinery, appliances) and consumers, through higher input costs

Steel-using industries employ far more Americans than steel-producing ones do, so the tariff concentrates benefits on producers while spreading costs broadly.

Roughly $1+ billion per year in added costs to downstream industries per percentage point of the tariff (estimates vary by methodology)

Precise figures vary widely across studies; the headline point is that costs land on steel users, not foreign governments.

Source: Tax Foundation — Trump tariffs analysis