When House Speaker Nancy Pelosi flew into Taiwan on an Air Force passenger jet Tuesday, she became the highest-ranking American official in 25 years to visit the self-ruled island. China announced military maneuvers in retaliation, even as Taiwanese officials welcomed her and she headed to her hotel. The reason her visit ratcheted up tension between China and the United States: China claims Taiwan as part of its territory, and it views visits by foreign government officials as them recognizing the island’s sovereignty. Read: US will not abandon Taiwan as China protests: Pelosi President Joe Biden has sought to calm that complaint, insisting there’s no change in America’s longstanding “one-China policy,” which recognizes Beijing but allows informal relations and defense ties with Taipei. Pelosi portrays her high-profile trip as part of a U.S. obligation to stand with democracies against autocratic countries, and with democratic Taiwan against China. A look at some of the issues at play: WHY DID PELOSI GO TO TAIWAN?