As the United Nations marks its 80th anniversary, its humanitarian operations are increasingly in doubt. Its top donor, the United States, has cut funding under the Trump administration and some other Western countries have followed suit. U.N. aid activities were once a bright spot of work by the world body. Workers have long brought food, water, shelter, medical support and other relief to people in urgent need amid conflict, repression, natural disasters and other crises. Now the U.N. and its partners are under increasing funding pressures in the work to save millions of lives.