Why 2 Chinese aircraft carriers are operating in the Pacific together for the first time

Japan this week confirmed that two Chinese aircraft carriers have operated together for the first time in the Pacific. That fuels concern about Beijing’s rapidly expanding military activity far beyond its borders. Carriers are considered critical to projecting power at a distance. China routinely sends vessels to areas around disputed East China Sea islands, but now it's going as far as what’s called the second-island chain which includes the U.S. territory of Guam. A single Chinese carrier has ventured into the Pacific in the past, but never east of that chain until now. China has the world’s largest navy numerically.