In 1972, US president Richard Nixon, with the advice of Kissinger, undertook a masterstroke in 20th-century diplomacy by opening up to China to counterbalance the threat of the Soviet Union. A quarter of a century later, the US-China rapprochement propelled China to become the world's second-largest economy, but the US now considers China a rival, creating cold war version 2.0, with a strange mix of competitors and allies.