President Obama and Prime Minister Julia Gillard are expected to announce an increase in the number of U.S. Marines rotating through Australian bases around the northern coastal city of Darwin, which serves as a critical gateway to Southeast Asia through Indonesia and East Timor. U.S. officials say the United States is not setting up any permanent military bases in Australia. Instead, the United States will rely on Australian military facilities, while withdrawing forces from Afghanistan as the war draws down. The activities of the U.S. Marines will include training and joint exercises. The United States and Australia are also discussing the prepositioning of supplies to better respond to natural disasters. This according to the Center for Strategic & International Studies
This is a move seen by many as a signal to China that the U.S. is not going to cede this region of the world to Beijing. While the troops are small in number, they serve as both a tripwire and a reminder to the world that the United States is still a force to be reckoned with and a counterweight to Chinese expansion plans.
This region also includes the Straits of Malacca, a “choke point” for oil supplies and other goods to the Far East. It is also centered in Indonesia, which has the highest population of Muslims in the world. If this nation should fall to radical Islam, China, Japan, and the other countries of Eastern and Southeast Asia would be vulnerable.