President Joe Biden 's recent approval of a major shift in U.S. nuclear weapons strategy highlights the attention the country's national security officials are paying to Chinese ambitions for influence in the world. As changes emerge in the types of threats facing the United States, the American military adjusts its strategic focus, budgets and planning. For instance, after 9/11 , the U.S. military refocused away from its Cold War emphasis on preparing for combat against a powerful nation --