Almost by definition, Mr. Obama lives a life foreign to most Americans, with the big white house and the ushers and chefs and the airplane fueled and ready to go. When he wants a weekend away, he can fly to Florida to golf with Tiger Woods. When his daughters take spring break, they head to Aspen to ski. He winters in Hawaii and summers on Martha’s Vineyard. But this summer’s trips come as federal employees are tightening their belts. Last Friday, four federal agencies closed down — the Environmental Protection Agency, the Internal Revenue Service, the Department of Housing and Urban Development and even the Office of Management and Budget — as employees were ordered to take the first of several unpaid days off. Many workers are canceling summer vacations of their own. Across the government, cutbacks are everywhere. The Blue Angels did not fly at the Naval Academy commencement, Head Start programs are turning away children, and there are no summer jobs for college students to cut the grass at Antietam.