Strengthening relations with Southeast Asia will not come easily for the United States after two decades of complacent engagement. Vice-President Kamala Harris is the latest and highest-profile of a string of senior officials from American leader Joe Biden ’s administration to travel to the region to bolster economic and military ties to counter China’s rise. During visits to Singapore and Vietnam, she outlined Washington’s vision for peace, stability and cooperation, agreeing to deals and offering support including maritime security and more Covid-19 vaccines . But those she met chose their words carefully; governments have nothing to gain from picking sides. Harris criticised Beijing on both stops, saying Washington’s aim was peace and stability, freedom of the seas, unimpeded commerce, advancing human rights, a commitment to the international rules-based order and “the recognition that our common interests are not zero-sum”. The Biden administration sees China as the US’ biggest rival “and geopolitical test of the century” and believes it can offer a counterweight through trade and security. Like Defence Secretary Lloyd Austin and Deputy Secretary of State Wendy Sherman during their recent Southeast Asian trips, she identified Beijing’s territorial claims in the disputed waters of the South China Sea as the key threat to regional stability. But the countries that have competing claims have a mechanism to deal with differences, and the warships that Washington and its allies are sailing through the area agitate rather than ensure peace. Singaporean and Vietnamese officials were bound to respond carefully to Harris’ overtures. China is important for trade, investment and infrastructure development, but the US also offers a balance and, for those countries concerned about Chinese military expansion, security. Singapore’s prime minister, Lee Hsien Loong, spoke of the “benign and constructive influence of the United States as a regional guarantor of security and support of prosperity”. His Vietnamese counterpart, Pham Minh Chinh, meeting with the Chinese ambassador before Harris arrived, said his country did not align itself against any other. US against ‘zero sum’ Asia ties but will stand up to China, Harris says Beijing pre-empted Harris’ visit with a delivery of much-needed vaccines as part of a pledge for 2 million doses; the US has promised a further 1 million. Vietnam is struggling with its worst outbreak yet of the coronavirus, exacerbated by a low vaccination rate. Beijing and Washington are well placed to help the region fight Covid-19, but they are also important to its economic recovery. The Biden administration’s assertive posture is aimed at building an alliance against China. Southeast Asia’s on-the-ground realities make that difficult.