President Trump has repeatedly made clear that he likes the idea of getting other countries to pay for US military operations that benefit them, and that showed up today in the ongoing buildup on the Korean Peninsula, with Trump talking up how incredible the THAAD missile defense system is, and that it “would be appropriate” for South Korea to pay for the billion dollar system’s deployment.

South Korea didn’t like that idea too much, and since the THAAD deployment is subject to an actual agreement, they were quick to point out that the agreement required them to provide a site and infrastructure for the deployment, while the US paid for deployment and operation.

The THAAD is intended to protect targets in the area around Korea from North Korean missiles, though its effectiveness in actual situations is seen by most experts as extremely limited, and the it would be of little use if the US did launch a full-scale war against North Korea, as most retaliation would be artillery, not missiles.

Trump’s notion that he might be about to get South Korea to pay for the costly system is the latest in a string of such notions that has come very much after the fact, with the US already having agreements in place that don’t oblige the other nation to offer them any sort of payment,, and no real reason for anyone to expect that they’d suddenly offer to do so just because Trump suggested it would be “appropriate” of them to offer.