For much of the past six years

For much of the past six years, President Obama has talked about working toward a world without nuclear weapons. Yet his administration is now investing tens of billions of dollars in modernizing and rebuilding America’s nuclear arsenal and facilities, as The Times reported in detail on Monday. And after good progress in making nuclear bomb material more secure around the world, Mr. Obama has reduced his budget requests for that priority. This is a shortsighted and disappointing turn.