Both sides of the Taiwan Strait are girding for would be the most difficult seaborne invasion since World War II.

Taiwan’s new opposition leader took office on Saturday, warning of the risk of war with China and pledging to open a new era of peace with Beijing.

The United States and China have agreed to set up military-to-military channels to “deconflict and deescalate any problems” following the “historic” meeting between the countries’ leaders, Donald ...