The US has pulled the last functional military units out of Panama, leaving behind 600 "caretaker" troops who will leave in December under the terms of President Carter's 1977 canal giveaway treaty. This has put a severe strain on US military efforts to support the anti-drug war in Colombia, Ecuador, and Peru. New bases in Arabua, Curacao, and Ecuador can cover about 80% of the same area but leave major corridors open. Steve Cole