U.S. Supreme Court MCBOYLE v. U. S., 283 U.S. 25 (1931)

[Page 283 U.S. 25, 27]

It is impossible to read words that so carefully enumerate the different forms of motor vehicles and have no reference of any kind to aircraft, as including airplanes under a term that usage more and more precisely confines to a different class. The counsel for the petitioner have shown that the phraseology of the statute as to motor vehicles follows that of earlier statutes of Connecticut, Delaware, Ohio, Michigan and Missouri, not to mention the late Regulations of Traffic for the District of Columbia, title 6, c. 9, 242, none of which can be supposed to leave the earth.

Although it is not likely that a criminal will carefully consider the text of the law before he murders or steals, it is reasonable that a fair warning should be given to the world in language that the common world will understand, of what the law intends to do if a certain line is passed. To make the warning fair, so far as possible the line should be clear. When a rule of conduct is laid down in words that evoke in the common mind only the pleture of vehicles moving on land, the statute should not be extended to aircraft simply because it may seem to us that a similar policy applies, or upon the speculation that if the legislature had thought of it, very likely the picture of vehicles moving on land, the United States v. Bhagat SinghThi nd, 261 U.S. 204, 209, 43 S. Ct. 338.

Judgment reversed.