1. It is not true that a principal has, in the ordinary transactions of life, an unlimited right to construe the powers and disavow the acts of his agent. Although an agent may have construed his powers in a different manner from that in which his principal intended that they should be understood, yet if he can make it appear that he has exercised ordinary diligence and acted with good faith, he has a right to enforce his construction against that of his principal, and the law will sustain him in it. A merchant, for example, addresses a letter of instructions to a shipmaster or supercargo, and the latter in consequence makes contracts which the principal did not intend that he should make; the principal will nevertheless be bound by them, unless he can show that the agent has been guilty of neglect or fraud; for it is his own fault if he has not made his instructions intelligible, or has chosen his agent so badly that he cannot understand plain language. The argument from analogy, and it is the only one by which the Vice-President undertakes to support his main position, therefore fails entirely. If the attitude of the General Government toward the States be the same as that of an agent in relation to his principal, it then follows that the General Government has a right to enforce its construction of the Constitution against that of the States, provided always that it act with good faith, and in the exercise of all the diligence and attention which the case requires. 2. But admitting even that, in private affairs, a principal has an unlimited right to construe the powers and disavow the acts of his agent, we cannot agree with the Vice-President, that it is impossible to assign a reason why _any single State_ has not an equally good right to annul at discretion the acts of the General Government. We think that at least two very sufficient reasons may be given, why this conclusion would not follow.