China has not ruled out using military force to achieve its ambitions with Taiwan. However, the U.S. continues to support Taiwan's autonomy, providing it with state-of-the-art weapons and military training. If China takes Taiwan, some experts have said it give it a greater advantage in the Indo-Pacific region, and the enable to threaten U.S. bases as far away as Guam and Hawaii.
Biden made the comments early on Monday in a visit to Japan for talks with leaders of the "Quad" group, which includes Australia, Japan and India. He said China was "flirting with danger" in its aggressive policy towards the self-governing island. Speaking about whether the U.S. would defend the island if Beijing attacks, Biden said: "That's the commitment we made."