Reference has been made by Mr. Henry, in a part of his communication quoted in the last chapter, to a proceeding in the House of Representatives, which has been called the “Covode Investigation.” It is proper that a detailed account of this occurrence should be here given. Among the lower, or rather the lowest, political tactics, inculpation of a retiring administration has often been resorted to for promoting the success of the opposite party, and it seems not infrequently to have been the calculation that the effect produced would be in proportion to the grossness of the imputations. Mr. Buchanan could not hope to escape calumny. None of his predecessors, not even the most illustrious of them all, not even Washington himself, had escaped it. Scarcely any of them, however, had been made the object of this kind of attack, by a method so base and by means so foul, as those to which President Buchanan was now to be subjected. Before any of the troubles of secession arrived, before either of the political parties had made its nomination for the next Presidential election, it was determined that an assault should be made upon him that would render him and his administration odious to the people of the country. It is certainly unavoidable, perhaps it is well, that free governments should be administered by parties. In a vigilant, jealous and active opposition, there is great security against the misuse of power by those who hold it. But the freedom of opposition, like the freedom of the press, can easily degenerate into licentiousness; and the greater the latitude allowed by the political maxims or habits of a people, the greater will be the danger of abuse of that right of criticism and inculpation which is essential to liberty, to purity, and to the public interests. Happily, there are some restraints upon the exercise of this right, imposed by the forms of procedure which our Constitution has prescribed when the conduct of the executive branch of the Government is to be called in question by the House of Representatives. When these restraints are violated, as they were violated against President Buchanan, there is but one judgment for history to pronounce. Those who institute a proceeding that is out of the limits of their constitutional function, for the purpose of exciting hatred of one who fills for the time a coördinate and independent department of the Government, and who conduct such a proceeding in secret, leave upon the records of the country a condemnation of themselves; and it is some evidence of the progress which a people are making in freeing their partisan warfare from such abuses, if we are able to say, as probably we can say, that such a proceeding would not be tolerated at the present day by any portion of the people of this country, as that which was begun and prosecuted against President Buchanan in the spring and summer of 1860.