Taiwan (Republic of China) and China (People's Republic of China) are de facto separate countries, but China maintains that Taiwan is a Chinese province and that eventual unification is inevitable. The United States ceased formal diplomatic relations with Taiwan in 1979 in favor of China, but informal relations have continued through the American Institute in Taiwan and the Taipei Economic Cultural Representative Office in Washington, DC. Taiwan has never formally declared independence from China, and China has stressed that formal independence would be a "red line," potentially leading to invasion. As of October 2022, China demands diplomatic exclusivity; that is, any state that has diplomatic relations with China must cut off formal diplomatic relations with Taiwan.