It wasn’t yet 3:30 p.m., and already there were heated words at the entrance to West Holt High School in Atkinson, Nebraska. The school was playing host to a State Department public hearing on Keystone XL — a proposed pipeline meant to carry synthetic crude oil pumped from the Alberta tar sands in Canada nearly 2,000 miles to Port Arthur and Houston on the Texas Gulf Coast. Yesterday’s hearing came hard on the heels of a contentious gathering at the Pershing Auditorium in Lincoln on Tuesday and was one of eight such listening sessions crammed into a week of marathon hearings in cities and small towns across the six states the pipeline would cross, all in an effort to settle whether such a project is in the national interest. But, for the moment, the debate was focused on a more basic question: Who would be allowed to speak?