In an example of how not to negotiate national security issues, Secretary of State John Kerry triggered confusion and consternation for key ally South Korea on U.S. deployment of the THAAD (Terminal High Altitude Area Defense) missile defense system.

Just as Washington was finally gaining momentum for deploying a system that would significantly improve anti-missile protection for South Korea and U.S. forces stationed there, Kerry committed a serious diplomatic faux pas.

It was the equivalent of declaring that police officers wouldn’t be necessary if people simply stopped committing crimes.

During a joint press conference with his Chinese counterpart Wang Yi last week, Kerry announced, “We have made it very clear that we are not hungry or anxious to deploy THAAD. The only reason for THAAD being in consultation … is because of the provocative actions of North Korea, which has publicly announced it is focused on the United States and which is developing weapons which have the ability to attack the United States. If we can get to denuclearization, there is no need to deploy THAAD.”

It was the equivalent of declaring that police officers wouldn’t be necessary if people simply stopped committing crimes—theoretically correct, but idealistic, unrealistic, and unhelpful. The South Korean media collectively interpreted Kerry’s comments as a shift in policy, suggesting that the U.S. now saw THAAD as merely a negotiating chip for Chinese agreement to tougher U.N. sanctions on North Korea instead of a necessary improvement to South Korean defenses against the growing North Korean nuclear and missile threat.

The issue played to innate South Korean fears of abandonment by the United States. Coupled with parallel reporting that the Obama administration had secretly discussed a peace treaty proposal with North Korea, South Korean pundits and press warned that the U.S. was again sacrificing Seoul’s interests in its own quest to improve relations with Pyongyang and Beijing. References to previous U.S. “abandonments” and Seoul again being the “shrimp amongst whales” while others negotiated its fate were common.

Assistant Secretary of State for East Asia Daniel Russel sought to repair Kerry’s broken crockery. While in Seoul, Russel declared:

There’s no connection between what is going on in the diplomatic track in the U.N. Security Council and the question of the deployment of THAAD. THAAD is not a diplomatic bargaining chip.

South Korea also tried to counter the growing perception of a U.S. flip-flop on THAAD. The Ministry of Defense spokesperson commented that the U.S.-South Korean THAAD talks were “launched upon the shared understanding that it could help defend South Korea and is needed to protect American citizens living in South Korea. That understanding is still effective. The U.S.’ position is predicted to stay put.”

After years of South Korean timidity to even admit it was considering U.S. deployment of THAAD, South Korean President Park Geun-hye announced after the recent North Korean missile launch that Seoul would begin bilateral discussions with Washington on the missile system. Her approval ratings increased in response to her decisive action, and over two-thirds of poll respondents supported THAAD deployment. The South Korean media and National Assembly members turned on a dime and abandoned their previous mass mischaracterizations of THAAD capabilities and fear of how China would react to South Korea improving its security.

Until Kerry’s remarks, there was strong South Korean consensus on the need to overcome the inadequacies of the nation’s indigenous missile defense system and stand up to Beijing’s attempts to impinge on South Korean national security interests. This has been replaced by uncertainty over the Obama administration’s policy and resentment over a possible U.S. abandonment.

Park Geun-hye had stepped up to the plate on THAAD. Unfortunately, Kerry threw her a brush-back pitch.