Buoyed by growing economic and military strength, China is drawing more lines in the sand in the vast, but disputed, offshore zones in Asia over which it claims sovereignty or jurisdiction. These "red lines," which China warns should not be crossed, affect the vital interests of Taiwan, Southeast Asia and Japan.
They also test the resolve of the United States to continue to support a treaty and partnership system with its allies and friends that has been a foundation for stability and growth in East Asia since the end of World War II.
China wants to tilt the balance of power in the region so that it has more influence and the U.S. less. But the red line policy is a challenge for China as well: how will it react if the lines it draws are crossed by the U.S. and other countries?