Yesterday, Secretary of State Mike Pompeo announced an important shift in U.S. declaratory policy on the South China Sea. This morning, Assistant Secretary of State David Stilwell elaborated further during remarks at CSIS’s annual South China Sea Conference. The press statement from Pompeo listed specific Chinese maritime claims the United States considers illegal. The statement marks a significant clarification of prior U.S. positions but not a radical break from past policy. It makes explicit things that had been implied by previous administrations. And in that it sets the stage for more effective diplomatic messaging and stronger responses to China’s harassment of its neighbors. U.S. partners and allies in the region were seemingly briefed in advance—the Philippine defense secretary, for instance, was ready with a positive statement within hours. And the new policy sparked excited, and often hyperbolic, coverage in the press and social media.