China’s relationships with several nations, from the U.S. to India, have soured in recent times. The decline in its ties with Australia has been particularly sharp — and carries risks for both sides. Not so long ago, Sino-Australian relations seemed on a much healthier track. China’s leader Xi Jinping addressed Australia’s parliament in 2014. The two countries got cozier still with a Free Trade Agreement enacted in 2015. Bilateral trade jumped and China continued to invest heavily in