By making a rare second trip this year to Vietnam, Defense Secretary Jim Mattis is signalling how intensively the Trump administration is trying to counter China’s military assertiveness by cozying up to smaller nations in the region that share American wariness about Chinese intentions, Associated Press reports. In an interview with ‘60 Minutes’ on Sunday, U.S. President Trump suggested that Defense Secretary James Mattis could be one of the next administration officials to depart his Cabinet. Earlier this month, Japan and Vietnam signed an agreement to work together to maintain peace and security in the South China Sea, where Hanoi and other countries are engaged in a territorial dispute with Beijing.