Children use the phrase when playing war in the backyard. If one in the group says that “the coast is clear” it means that it is safe for the group to advance. No enemies threaten. Whether or not a coast is nearby is irrelevant. The message suggests that the group can change position with minimal risk of being attacked, a fearsome prospect to children playing at war.
The origin of the phrase is not clear, though some speculate that it may have been used as a signal to begin a coastal smuggling operation. Whatever its origin, the phrase is used without thought given to its maritime association because it is a convenient way to describe a variety of circumstances.
“The coast is clear” might have been in use as far back as the 16th century. If so, it would have been a convenient phrase to use during the early years of exploration and exploitation of the New England coast. A ship at the end of westward sail across the Atlantic would often make landfall on an island rather than the mainland. This was just as well because an island is easier to explore and defend than a vast wilderness with a potentially hostile coast. The earliest profitable English fisheries were established on islands not just because the fish were offshore but because an island was a relatively secure location. The “main” or the mainland coast was less appealing because it was unmapped and settled by native people whose cultures were unfamiliar to the English. It was not clear what threat lurked at the head of a beach.
The French were better at befriending the Indians than the English. Together, the French and Indians gave English settlers on the Maine coast the jitters and King Phillip’s War was a lesson that no coast was clear. Fur trappers were more likely than fishermen to advance into the mainland but they would have expected their every move to be observed by those whose knowledge of the forest was superior to theirs. A trapper would want assurance that the coast is clear of human threats before he leaves the ship that brought him to New England and he enters the deep woods. “Is the coast clear?” was a reasonable question to ask, considering the territory.
If a clear coast is a blessing and a relief then an “unclear coast” is a symbol of vulnerability and risk that always includes the threat of violence. The best example of this is the Allied invasion of Normandy on June 6, 1944, “D-Day.” To nervous German coast guards the sight of the vast fleet that lay off the beaches was a sign that on that day, the coast was not clear. To the equally nervous sailors, soldiers and marines in that fleet the sight of the shore batteries was a sign that the coast was not clear to them either. An advance into an unclear coast will often take a human toll.
“The coast is clear” is a convenient way of saying that circumstances are favorable for any number of prospects. Teen lovers pursue their interests when parents are absent and the coast is clear. An employee who does not want to face his boss might ask the office manager if the coast is clear. A politician might interpret his election as meaning that the coast is clear for change. The maritime history that gave birth to the phrase is no longer relevant nor even understood but it is still a useful set of words. It expresses the best situation that circumstances will allow. If it weren’t for the humanity that gives the phrase its life, “The coast is clear” would be just another weather report.
— Randy Purinton