On March 2, 1942, the petitioner, therefore, had notice that, by Executive Order, the President, to prevent espionage and sabotage, had authorized the Military to exclude him from certain areas and to prevent his entering or leaving certain areas without permission. He was on notice that his home city had been included, by Military Order, in Area No. 1, and he was on notice further that, at sometime in the future, the Military Commander would make an order for the exclusion of certain persons, not described or classified, from various zones including that, in which he lived.
March 21, 1942, Congress enacted [n3] that anyone who knowingly
shall enter, remain in, leave, or commit any act in any military area or military zone prescribed . . . by any military commander . . . contrary to the restrictions applicable to any such area or zone or contrary to the order of . . . any such military commander