New Delhi, May 13 -- It's a verbal tightrope American presidents have had to walk for nearly 50 years, where even small slip-ups when stating official U.S. policy toward Taiwan and China can trigger geopolitical alarm bells.

The way the U.S. views Taiwan under the "One China" policy recognizes the Chinese position that Taiwan is part of China, while still allowing for informal U.S. relations with the self-governing island.

It is intended to be vague - built on what's become known as strategic ambiguity. That is, the U.S. has agreed to ensure Taiwan has the resources to defend itself if China attempts to force a unilateral change, without saying how far it will go militarily to counter Beijing.

As assistant U.S. defense secretary Joseph...