The issue of gray zone conflict between the US and China has attracted much attention in recent years. “Gray” indicates actions below the threshold of war, yet beyond normal diplomacy. The fundamental characteristics of gray zone activity include that they are well-planned, designed to be ambiguous amid strategic competition, and intended to leave opponents unable to launch an effective response. What demands special attention is that gray zone activity could cause unintended escalation, and that assertive responses to them may not be the best option. For instance, the United States’ gray zone retaliation to China’s activities in the South China Sea is hardly helpful to contain China’s activities, but certainly slow the pace of resolving the South China Sea dispute through negotiation and dialogue and jeopardize bilateral strategic stability.

In the United States, current studies on the gray zone issue view the activity conducted by “measured revisionists” (such as Russia, China and Iran) as a major challenge to US national interest and the US-led international order. Today, as China and the United States are dancing on the precipice of a trade war, the geopolitical rivalry between the two countries raises major concerns and the possibility of a new Cold War has been discussed with increasing frequency. Although the United States and China are highly interconnected in many ways, entanglement also creates friction. In this context, the gray zone issue between China and the United States has a significant role in the relationship. How do we understand gray zone conflict? What challenges does the current gray zone activity pose to China and the United States? What measures should be taken to address such challenges?

This paper argues that because gray zone activity undermines strategic stability, disrupts policymaking, and causes unintended escalation, these actions have become a “gray zone challenge” to both China and the United States. Given the difference between gray zone conflict and traditional conflict, traditional measures will not work well to address the “gray zone challenge,” the best antidote for it is multilateral norm building, not a competitive strategy. This paper concludes with four key policy recommendations to address the challenge.

• Both parties should work together to engage other countries in strengthening and in some cases developing multilateral mechanisms to address gray zone disputes.
• Both parties should recognize that systematic narrative campaigns that attack the other come with high risk and should be avoided.
• Both parties should prioritize work on creating a code of conduct on cyber security, promoting nonproliferation of cyber-attack techniques, and cooperatively enhancing the resilience of critical infrastructure.