Camp Pendleton has begun large-scale training exercises to prepare Marines to operate from a base in Darwin, Australia, early next year, part of a larger U.S. effort to deepen ties with a key ally in the Indo-Pacific. Darwin represents a potential staging point for the U.S., which has repeatedly said it will repel any attempt China makes to interfere with international trade routes in the South China Sea. The U.S. also has said it will confront China if it invades Taiwan, which China has threatened to do many times in recent years. Such a confrontation would affect the entire Indo-Pacific region. The new wave of training at Camp Pendleton began Monday and will last more than two weeks. Some exercises will extend far beyond the base to San Clemente Island, Marine Corps Air Station Yuma, and Beale Air Force Base in the Central Valley. Steel Knight 24, as the exercise is called, will prepare Marines to deploy to Darwin in March for a mission that will last until late summer. The training is meant to sharpen their ability to rapidly respond to a crisis, including the need to reinforce a U.S. embassy overseas. The Marines will train with the Australian Defense Force, something they’ve been doing there since 2012. This seasonal rotation has taken on a higher profile as tensions between the U.S. and China have increased. The U.S. and Australia have been military allies for more than 100 years, dating back to World War I. About 300 U.S. military are stationed in Australia, a number that could increase. In August, a think tank in Australia proposed that the country host as many as 16,000 Marines a year. The idea is only in the talking stages. But there’s already been action on other fronts. In March 2023, President Joe Biden and prime ministers of Australia and the United Kingdom held a press conference in San Diego to announce that they’ll work together to beef up Australia’s small submarine force.