Mr. Obama described his policy as part of a broader effort to edge the world toward making nuclear weapons obsolete, and to create incentives for countries to give up any nuclear ambitions. To set an example, the new strategy renounces the development of any new nuclear weapons, overruling the initial position of his own defense secretary.
For the first time, the United States is explicitly committing not to use nuclear weapons against nonnuclear states that are in compliance with the Nuclear Nonproliferation Treaty, even if they attacked the United States with biological or chemical weapons or launched a crippling cyberattack.
Those threats, Mr. Obama argued, could be deterred with "a series of graded options," a combination of old and new conventional weapons. "I'm going to preserve all the tools that are necessary in order to make sure that the American people are safe and secure," he said in the interview in the Oval Office.