But how is the Executive to ascertain the behest of the people? In accordance with the modes which they, as a part of their behest, indicate. But as there are two methods of fulfilling the wishes of the people, one adapted to the ordinary routine of peaceful times, and another to the more summary necessities of war, so there are two methods, calculated for these diverse national states, by which the Government must discover the will of the people. The slow, deliberate action of the ballot box and of the legislative body is amply expeditious for the purposes of undisturbed and tranquil periods. But in times of rebellion or invasion, the waiting and delay which are often essential to the prosecution of forms prescribed for undisturbed epochs are, as has been said, simply impossible. War is a period in which methods and procedures are required diametrically opposite to those which are so fruitful of good in days of peace. The lawbreaker who comes with an army at his back cannot be served with a sheriff's warrant, nor arrested by a constable. War involves unforeseen emergencies, to meet which there is no time for calling Congress together, or taking the sense of the populace by a ballot. It is full of attempted surprises, which must be guarded against on the instant, and of dangers which must be quickly avoided, but for whose guardance or avoidance the statutes make no provision. Hence arises a necessity for a mode of ascertaining the will of the people other than the slow medium of formal legislation or of balloting.