His conscience commanded him to stand by slavery as the fundamental condition of his people's well-being; it also at the same time commanded him to strain all his energies to save the union by making it the protector instead of the assailant of slavery. This was the insuperable task which the powers in the unseen put him in the treadmill to do. From the time he commenced the discussion of the anti-slavery petitions until his exclamation over the "poor south," on his death-bed, life was to him but a deepening agony of solicitude and utmost effort,--solicitude for his country and section, effort to avert the danger that became greater and more awful to him every day. He strove after remedies under the constitution. The more he recalled the success of the single stand of South Carolina against the tariff, the prouder he became of being the author of nullification. Its dearness to him was that it was peaceable as well as efficient. The better opinion of the State-rights school is that nullification is an absurdity, and that South Carolina's only true remedy against the tariff was to secede if it were not repealed. But he knew better than everybody else that secession meant internecine war between the sections, and this influenced him to exalt peaceable nullification above bloody secession. It needs not to consider each barrier, whether party combinations, admission of new slave States, legislation, etc., that he tried to erect against the incoming oceanic wave. But we must briefly consider the amendment of the constitution which he proposed. He wanted the north and the south each to have a president, as he said, "to be so elected, as that the two should be constituted the special organs and representatives of the respective sections in the executive department of the government; and requiring each to approve all the acts of congress before they shall become laws."[62] Do this, he urged, and neither section can use the powers of government to injure the other, for whatever proposed law menaces a section will be vetoed by its president. It profits the student of the science of government to consider the historical examples which Calhoun adduced here. They are indeed so apt that the hearing which has ever been denied him should be granted him at least academically. He says: "The two most distinguished constitutional governments of antiquity both in respect to permanence and power had a dual executive. I refer to those of Sparta and Rome."[63] It is interesting to be informed that those same wise Iroquois from whom our fathers probably got the precedent of the old confederation, put in practice something very like what Calhoun advises. We append both the account and instructive comment of Morgan: