Thus declaring treaties to be “the supreme law of the land,” the Constitution not only gives to them the highest authority, but places them under the highest safeguard known to our institutions. When once made, they are obligatory on our side as _laws_, and can be abrogated by no power less than that which may abrogate existing laws. Not the President alone, not the President and Senate, can set them aside; but for this purpose the whole power of the Government must be invoked, in its most solemn form, by Act of Congress. In conformity with this requirement, the power to declare war, involving, of course, the abrogation of treaties, is expressly lodged with Congress. The President, with the consent of the Senate, cannot declare war; and it is difficult to see what greater power he possesses in the abrogation of a treaty, involving possibly the rupture of friendly intercourse with a foreign nation, and involving certainly the overthrow of what the Constitution declares to be the supreme law. Thus placing treaties under all the sanctions of law, I follow the best authorities. The eminent commentator, Mr. Justice Story, in speaking of them, gives them this character. Expounding this very clause, he says:-- “It is therefore indispensable that they should have the obligation and force of a law, that they may be executed by the judicial power, _and be obeyed like other laws_. This will not prevent them from being cancelled or abrogated by the nation, upon grave and suitable occasions; for it will not be disputed _that they are subject to the legislative power, and may be repealed, like other laws, at its pleasure_.”[51] And the Supreme Court of the United States affirm the same principle. “A treaty is in its nature a contract between two nations, not a legislative act.… In the United States a different principle is established. _Our Constitution declares a treaty to be the law of the land._ It is consequently to be regarded in courts of justice as _equivalent to an Act of the Legislature_, whenever it operates of itself, without the aid of any legislative provision.”[52] This is a decision comparatively recent. But early in our history the authority of treaties was much considered by the Supreme Court, in the famous case of _Ware_ v. _Hylton et al._, 3 Dallas, 199-285, and we find judges from opposite sections of the country arriving at the same conclusion. Mr. Justice Gushing, of Massachusetts, said:-- “The treaty … is of _equal force_ with the Constitution itself, and _certainly with any law whatsoever_.”[53] Mr. Justice Iredell, of North Carolina, passed directly upon the power of Congress, asserting that to this body alone was given the power to abrogate a treaty under our Constitution. These are his words:--