The United States and Australia are currently finalizing a deal that will see a number of U.S. B-1 bombers deployed to Darwin. While not officially confirmed by the Australian government, U.S. Pacific Air Force Gen. Lori Robinson made the announcement to media sources on Tuesday.

Robinson outlined the rotation plan that will send B-1 bombers to air bases in Darwin and Katherine. There the U.S. will train alongside Australia’s Air Force, rotating in and out on an ad hoc basis. While many are hailing it as a proactive step in maintaining military dominance over China in the region, the maneuver also highlights the growing military prowess of the Chinese.

The key point to notice is that the B-1 bombers will be sent to Australia from Guam, not from Hawaii or the U.S. mainland. Since the 1940s, the island of Guam has been key to America’s projection of power into Southeast Asia. The island is home to one of the United States’ four key forward-bomber bases.

Location and size make Guam ideal for a U.S. airbase. Situated almost 4,000 miles west of Hawaii, the island is pivotal in U.S. efforts to maintain a dominant and near-at-hand military presence in Asia. The island is within range of the region’s pivotal sea-lanes and areas of contention, particularly the South China Sea.

However, China’s advancements in missile technology and its creation of man-made islands in the region bring Guam into China’s range too.

Until recently, Guam sat just outside China’s missile capabilities. But as U.S. think tank Stratfor pointed out in an article this week, China’s development of intermediate-range ballistic missiles now puts the U.S. airbase well within China’s reach.

As the saying goes, you shouldn’t put all your eggs—or bombers—in one basket.

Thus, the U.S. has been looking to diversify throughout the region. The U.S. Department of Defense issued a statement in February stating that it would use Tinian Island, just north of Guam, as a preferred alternative airfield “in the event access to Andersen Air Force Base, Guam, or other western Pacific locations is limited or denied.”

This is where Australia comes into play. Darwin is still outside China’s missile range—though only just. The U.S. can serve two purposes by deploying its bombers from Guam down to Australia. First, the move strengthens the U.S.-Australia military alliance; and second, it protects bombers from Chinese missiles.

The latest Chinese intermediate-range ballistic missile, the DF-26, can travel at speeds up to Mach 10, or 7,672 miles per hour. It has a range of over 2,170 miles and can destroy a U.S. supercarrier in a single strike. So it’s clear why the U.S. is looking to diversify its bases in the region.

This week General Robinson also announced that three of America’s 20 operational B-2 stealth bombers would be coming to Southeast Asia, though she did not mention where or how long they would stay. During the press conference, the general stated, “Recent events demonstrate the continued need to provide consistent and credible airpower throughout the Indo-Asia-Pacific region.”

Those recent events surround the rise of China and its subordinate, North Korea.

In recent months both powers have aggressively pushed back at U.S. dominance in the region. China has gone further, reaching out economically to the region through means such as the Asian Infrastructure Investment Bank—another tool to counter Western influence.

The wrestle for power between the U.S. and a rising China has placed Australia in a tough situation. China is Australia’s number one trade partner. Chinese investment is what saved Australia in 2008 through the mining and housing boom. That investment still plays a large role in propping up the housing market today. As for trade, 60 percent of Australia’s trade passes through the South China Sea.

Deals like the 99-year loan of the Port of Darwin to Chinese company Landbridge—with its strong ties to the Chinese People’s Armed Militia—shows Australia’s attempt to play both sides of the field. The move drew strong criticism from America, which was caught off guard by the sale. Adding to U.S. frustrations, Australia’s economic dependence on China means it has done little to condemn Chinese aggression in the South China Sea.

But Australia still needs to maintain a strong military alliance with the United States. That is why we see deals like the B-1 deployment, increased training, war games, etc. In doing so, Australia draws the ire of China.

As Stratfor noted, having the U.S. military stationed in the Northern Territory only gives China incentive to develop weapons capable of reaching Australia.

As China’s reach grows, Australia’s role is becoming more important. But U.S. and Australian efforts to contain China may already be too little too late. Just this week, U.S. Army Chief of Staff Gen. Mark Milley said, “The military’s antiterrorism and counterinsurgency focus of the last 15 years has shortchanged the Army’s training and preparedness to fight high-end threats, hybrid threats, enemy artillery and enemy electronic warfare.” The high-end threats he referred to are China, Russia, Iran and North Korea.

Keep watching as the U.S. strives to prevent itself from being outmaneuvered in Southeast Asia. While Australia and other U.S. allies in the region may be cooperative, the moving of bombers to Australia shows that Washington has been caught off guard by Chinese expansion into the region.