According to a new military doctrine signed by Russian President Vladimir Putin, NATO is the nation’s No. 1 military threat. The doctrine raises the possibility of using conventional weapons to counter aggression from other countries that “threatens the very existence” of Russia. It also says the country could use nuclear weapons in retaliation against nuclear or other weapons of mass destruction. Also, for the first time, the doctrine says Russia may use precision weapons “as part of strategic deterrent measures,” though it did not specify how or when the country could resort to such measures.