President Obama hosted a “townhall” meeting in Shanghai, accepting questions from his Chinese audience. One questioner gave Obama the opening to discuss the prospect of arms sales to Taiwan, an issue that is sure to arise when the President meets with Hu Jintao in Beijing.

Unfortunately, rather than forthrightly stating that the United States, in line with longstanding policy and the Taiwan Relations Act (TRA), was prepared to sell Taiwan defensive weapons, President Obama said nothing at all. Instead, he chose to dodge the question, noting that the US favored “dialogue and negotiations.”

The problem is that this answer does nothing to promote cross-Straits reductions in tensions. It is likely to mislead Beijing into thinking that the United States will forego arms sales—a dangerous impression to leave the Chinese leadership. At the same time, it is also likely to raise questions in Taipei about American willingness to abide by its commitments to Taiwan’s security—hardly a means of promoting Taiwan’s confidence in dealing with the mainland.

Worst of all, Taiwan’s ability to deter the PRC is steadily atrophying, as their air force ages. Taiwan has now repeatedly raised the subject of purchasing F-16 C/Ds, and will undoubtedly do so again. Should the United States decide to proceed with the sale, Obama’s misleading silence is more likely to engender anger from Beijing (which is likely to have interpreted his non-answer as a negative), making US-Chinese cooperation that much more difficult on future issues.

In this case, silence is not golden.