While much attention is focused on its behavior toward Taiwan, China is building and militarizing artificial islands in the South China Sea. It also broke ground on an expanded naval port in Cambodia last week, which may one day provide its first military foothold in another Asian country. A security agreement with the Solomon Islands could lead to something similar, and Beijing is aggressively courting other Pacific nations.

America’s military position in Asia, by contrast, has been hampered by decades of preoccupation with Middle East conflicts. The war in Ukraine has morphed into a long-term $54 billion commitment and forced Mr. Biden to delay and redraft his administration’s National Defense Strategy and National Security Strategy — critical documents that lay out global priorities and resource needs — as officials grapple with how to manage China and Russia at the same time.

Mr. Biden’s team ended the lengthy and costly U.S. involvement in Afghanistan, but that has not freed up many resources for the Indo-Pacific. Washington must not lose sight of the fact that China is a far greater security threat than Russia, now and in the long term.