Time has proven the discernment of our ancestors, for even these provisions, expressed in such plain English words that it would seem the ingenuity of man could not evade them, are now, after the lapse of more than seventy years, sought to be avoided. Those great and good men foresaw that troublous times would arise when rulers and people would become restive under restraint, and seek by sharp and decisive measures to accomplish ends deemed just and proper, and that the principles of constitutional liberty would be in peril unless established by irrepealable law. The history of the world had taught them that what was done in the past might be attempted in the future. The Constitution of the United States is a law for rulers and people, equally in war and in peace, and covers with the shield of its protection all classes of men, at all times and under all circumstances. No doctrine involving more pernicious consequences was ever invented by the wit of man than that any of its provisions can be suspended during any of the great exigencies of government. Such a doctrine leads directly to anarchy or despotism, but the theory of necessity on which it is based is false, for the government, within the Constitution, has all the powers granted to it which are necessary to preserve its existence, as has been happily proved by the result of the great effort to throw off its just authority...

This nation, as experience has proved, cannot always remain at peace, and has no right to expect that it will always have wise and humane rulers sincerely attached to the principles of the Constitution. Wicked men, ambitious of power, with hatred of liberty and contempt of law, may fill the place once occupied by Washington and Lincoln, and if this right is conceded, and the calamities of war again befall us, the dangers to human liberty are frightful to contemplate. If our fathers had failed to provide for just such a contingency, they would have been false to the trust reposed in them. They knew -- the history of the world told them -- the nation they were founding, be its existence short or long, would be involved in war; how often or how long continued human foresight could not tell, and that unlimited power, wherever lodged at such a time, was especially hazardous to freemen. For this and other equally weighty reasons, they secured the inheritance they had fought to maintain by incorporating in a written constitution the safeguards which time had proved were essential to its preservation. Not one of these safeguards can the President or Congress or the Judiciary disturb, except the one concerning the writ of habeas corpus.

-Ex parte Milligan, 1866

The words of Mr. Justice Davis are just as true -- and just as relevant -- today as when they were first written.