But there are three other sources, each of which is overflowing. The first is from the necessity of the case, _ex necessitate rei_. This is one of the grounds on which Chief-Justice Marshall asserted the power of Congress over the Territories;[7] but it is equally applicable in the work of Reconstruction. From the necessity of the case this power must be in Congress, as without it Reconstruction could not be completed. You must renounce Reconstruction or recognize this power. Then comes the “guaranty” clause, which is another bountiful, all-sufficient fountain. The United States are to guaranty a republican form of government to the States. But this guaranty can be executed only through Congress. This clause is at once old and new. It is old as the Constitution itself, but it is new in its practical exercise. And the reason is obvious. So long as Slavery prevailed, this mighty power slept; but it was the sleep of a giant. At last it has awaked, never again to sleep or slumber. From this time forward the duty of the nation to guaranty a republican government to all its parts will be constant and ever-present; and this duty is reinforced by all needful powers. The guaranty is continuing and perpetual, and it must be executed at all hazards. In its execution Congress must fix the definition of a republican government. How often have I said this!--but I shall not fail to repeat it so long as the occasion requires. To Congress belongs the duty of determining what is a republican government, and then it must see that such a government prevails in every State. If in any State the existing government fails according to the just standard, or if it is in any way menaced, then must Congress interfere to execute the sleepless guaranty. And in this interference it may act according to its discretion, determining the occasion and the “means” to be employed. It may act by repression or by precaution, and it may select any “means” proper for the purpose. To say that it may not act by precaution as well as by repression is contrary to reason, and I may say to common sense. Whatever may be done by repression may be done by precaution also. Such is the experience of life in other things, and this obligation of guaranty is subject to the universal law. In the selection of “means” the whole field and the whole arsenal are at its command. Not an instrument, not a weapon, proper for the purpose, which it may not grasp. Here the language of Chief-Justice Marshall, so often quoted, harmonizes with the claim of power which I now make:-- “The Government which has a right to do an act, and has imposed on it the duty of performing that act, must, according to the dictates of reason, be allowed to select the means; and those who contend that it may not select any appropriate means, that one particular mode of effecting the object is excepted, take upon themselves the burden of establishing that exception.”[8]