Agency`s Profile, and Its Duties, Have Grown Since Sept. 11. The public profile of the Coast Guard, whose traditional mission has been to patrol the coasts to stop illegal immigrants, drugs and other contraband, has been raised since Sept. 11. It now must also escort vessels into port, enforce safety zones around Navy ships, board commercial ships in search of chemical and biological weapons, and secure the nation`s ports. It does this with some of the oldest ships on the seas. Full Story