text:  Leaders from NATO countries, meanwhile, descending on Washington, D.C., ahead of a three-day summit, which begins tomorrow. As NPR's Jackie Northam reports, it's the 75th anniversary of NATO's founding. But ongoing concerns about Ukraine and American politics hover over the event. Ukraine is likely to dominate this year's NATO summit. The 32-member alliance is expected to announce new initiatives to shore up support for Ukraine, more weapons, training and funding.