In the stately caucus room of the Russell Senate Office Building, the U.S. Navy joined forces with the oil industry and AT&T Corp. the other day to lobby for a common objective: ratification in the next few months of the Law of the Sea treaty. The treaty regulates commerce, navigation and exploration on and beneath the oceans, and President Ronald Regan rejected it in 1982. Amended to satisfy U.S. objections, it was signed by President Bill Clinton in 1994 and sent to the Senate for ratification. There it has languished ever since.