GENEVA (AP) — The Trump administration's move to impose tariffs on countries like China undermines the rules-based system of global commerce that the United States itself helped create after World War II, experts and trading partners say.

Those rules are embodied and overseen by the World Trade Organization, which now sees its authority challenged and possibly diluted by the U.S. government's move to create tariffs without prior consultations — posing a threat to a trade architecture meticulously built up over decades.

"There is genuine systemic risk," said Joseph Francois, the managing direct...