he standard of review de- pends on the pgcise issue being litigated. See Cavallaro . United States, 284 F. 236, 245 (1st ir.2002); United States I Mass. Inst. of Tech., 129 F.3d 681, 683 (1st Cir.1997). We review rulings on questions of law de novo, findings of fact for clear error, and judgment calls-s