“South Korea has been protected by us for many, many years, and during my first term, they agreed to pay close to $3 billion a year for protection, because we don't, you know, they essentially weren't paying.”

South Korea never agreed to pay $3 billion a year. The only cost-sharing agreement signed in Trump's first term was a one-year accord in February 2019 that raised South Korea's contribution by about 8 percent, according to the Congressional Research Service, leaving the total under $1 billion. That accord expired on December 31, 2019, and talks on a successor were unresolved when he left office. Nor is it true that South Korea had not been paying: under cost-sharing agreements dating to 1991, it covered 40 to 50 percent of the non-personnel costs of U.S. forces, over $800 million a year.

His administration did demand far more: CRS cites press reports that it sought an increase of roughly 400 percent in the 2019 to 2020 talks. South Korea refused, and the agreement lapsed.