By Chris Adams

Controlling imports is often pitched as a purely domestic political issue – a crowd-pleaser for Donald Trump and Bernie Sanders alike, a thorn in the side of corporate America and traditional Republicans.

But whatever happens domestically on trade, the big conflicts will come when disputes over what the Trump administration has done are heard at the World Trade Organization.

In a National Press Foundation session, Jennifer Hillman, a professor at Georgetown Law Center, explained how the WTO works, as well as how she said recent actions have run afoul of its rules. Hillman has been a member of the Appellate Body of the WTO, a commissioner on the U.S. International Trade Commission, and a general counsel for the Office of the United States Trade Representative.

Hillman documented the range of Trump administration actions, including those on solar panels, washing machines, steel and aluminum. Whatever their status domestically, they have also been challenged in the WTO.

What is the WTO? Hillman described the international body, which is a forum to help countries negotiate trade agreements and to hear trade disputes. It seeks to arrive at a consensus among member countries, and those countries commit to being all-in on the process – if they agree to certain aspects of WTO rules, they must agree to all of them.

She also gave an overview of key WTO rules, such as most-favored nation status and the limits on tariffs that can be assessed. And she detailed the WTO’s dispute settlement system, which sees about 25 complaints filed per year.

Hillman has also written and lectured extensively on Brexit, the decision by the United Kingdom to withdraw from the European Union. She detailed Brexit’s timeline, from the 2016 referendum that started it to the expected withdrawal date of March 2019.

Pulling out is not going to be easy: The U.K. must replace, renegotiate or extend more than 700 agreements with the EU, and unwinding the relationship will be “very difficult and very time consuming,” she said.

Hillman also discussed the implications on European trade, as well as that in the United States. The U.S. is the largest investor in the U.K. Beyond that, more than 1 million Americans work for British companies in the U.S., and nearly 1.4 million Britons are directly employed by U.S. affiliates.