The Trump administration suffered another setback with the announcement that Joseph Yun, the U.S. special representative on North Korea policy, will be retiring:

The State Department’s point-man on North Korea, Joseph Yun, will leave his post on Friday, even as there are glimmers of hope that Pyongyang might finally be willing to sit down for talks with Washington.

Yun, 63, is retiring as special representative for North Korea policy and deputy assistant secretary for Korea and Japan after more than three decades of service.

His departure reflects the widespread frustration within the State Department at diplomats’ relative lack of power in the Trump administration [bold mine-DL], according to someone familiar with Yun’s thinking.

It will leave another gaping hole in the United States’ staffing on Korean issues. Washington has still not nominated an ambassador to South Korea, 13 months into the Trump administration. Victor Cha had been in the running for the job, but the administration abruptly scrapped his candidacy last month.

Yun’s retirement is part of the larger hollowing out of the State Department that has taken place over the last year under Tillerson, and it offers a little more evidence that the administration has no real interest in a diplomatic solution to the standoff with North Korea. The withdrawal of the Cha nomination showed that the Trump administration doesn’t care for regional experts that aren’t on board with their aggressive posturing. Now it seems that at least one of the top career diplomats with relevant regional expertise doesn’t see much point in staying on. Yun’s retirement deprives the administration of a valuable and knowledgeable advocate of engagement, and there were not many of those to start with.

There are mounting costs to the administration’s disdain for diplomacy and its determination to weaken the State Department, and this is one of them. If this were an isolated case, it might be possible to dismiss it as unrepresentative and not very significant, but in light of the hemorrhaging of personnel from the State Department over the last year the latest announcement takes on greater weight. The exodus of career diplomats is happening because they have concluded that the president and Secretary of State don’t value their knowledge and experience and have no interest in making use of them, and there is nothing to suggest that they are wrong to draw that conclusion.

The Yun retirement will further hamper an advocate for engagement with North Korea when that is needed more than ever, and it probably means that the administration has no interest in listening to what Yun has to tell them. That bodes very ill for the future of U.S. North Korea policy.