The first call came in to the U.S. Capitol early in the morning. A Capitol Police officer was too sick to work. Soon, another officer called with the same problem. Then another. And another. By the end of the Columbus Day weekend, more than 70 officers charged with protecting Congress had called in sick, an iillness brought on by fatigue. The constant and continual elevated terror alerts have meant weeks and weeks of 12-hour shifts, little vacation and fewer days off.