U.S. launches Section 301 probes against Korea, warns of tariffs.

The Trump-era U.S. administration on November 11 announced the start of Section 301 investigations targeting Korea and other countries, signaling that new tariffs could be imposed on nations that already have trade agreements with the United States. The move comes even as Korea and the United States have pledged substantial investment in each other’s markets.

Jameson Grier, head of the U.S. Trade Representative (USTR), said the existing trade deals would remain in place, but warned the 301 probe could lead to tariffs or other measures. He stressed that the investigations are separate from the concessions already made under mutual tariff agreements.

Korea’s government framed the action as an effort to restore mutual tariffs whose effect had been nullified by a federal court ruling. Officials emphasize that the goal is to preserve the existing trading deal as much as possible, while acknowledging that the 301 process could alter tariff arrangements.

Hang Yoo Han-koo, director-general of the Trade Negotiations Bureau at Korea’s Ministry of Trade, Industry and Energy, said the administration expects to restore the mutual tariffs to their pre-ruling level (15%) from mid-July, using the 301 mechanism. He cautioned that the 301 investigation operates on a different basis from the mutual tariffs.

Nevertheless, observers worry that 301 is not identical to the traditional tariff adjustments embedded in existing trade deals, raising uncertainty about outcomes for Korea’s partners and markets. The difference in mechanism could complicate how concessions are applied going forward.

In Seoul on the 12th, the Foreign Ministry met with Michael Disombrie, the U.S. deputy assistant secretary of state for East Asia and the Pacific, to press for non-disadvantaging treatment relative to other major economies. The U.S. side also raised concerns about the e-commerce firm Coupang, signaling that regulatory and competitive issues in tech platforms remain a point of sensitivity.

For U.S. readers, the developments matter because Korea is a major ally and a significant trading and investment partner. Last year Korea agreed to invest about $350 billion in the United States, underscoring the economic interdependence of the two economies. Tariffs or tariff threats under Section 301 could threaten those investments and ripple through U.S. supply chains, particularly in sectors where Korean technology and manufacturing play a key role.

Beyond Korea, the move touches on broader U.S. concerns about fair trade practices and how Washington handles trade disputes with allies. The outcome could influence not only Korea and Japan with which similar talks are referenced, but also how U.S. companies plan investments, sourcing, and market strategies across Asia.