The slavery extensionists endeavored to have the Missouri compromise line stretched on to the Pacific. Benton, avowing his belief that slavery was an evil, opposed this, and gave his reasons why he did not wish to see the line which had been used to divide free and slave soil in the French or Louisiana purchase extended into the lands won from Mexico. Slavery had always existed in Louisiana, while it had been long abolished in Mexico. "The Missouri compromise line, extending to New Mexico and California, though astronomically the same as that in Louisiana, would be politically directly the opposite. One went through a territory all slave, and made one half free; the other would go through territory all free, and make one half slave." In fact Benton, as he grew older, unlike most of his compatriots, gained a clearer insight into the effects of slavery. This was shown in his comments upon Calhoun's statement, made in the latter's last speech, in reference to the unequal development of the North and South; which, Benton said, was partly owing to the existence of "slavery itself, which he (Calhoun) was so anxious to extend." It was in this same speech that Calhoun hinted at his plan for a dual executive,—one president from the Free and one from the Slave States,—a childish proposition, that Benton properly treated as a simple absurdity.
In his speech against the compromise, Benton discussed it, section by section, with great force, and with his usual blunt truthfulness. His main count was the injustice done to California by delaying her admittance, and making it dependent upon other issues; but he made almost as strong a point against the effort to settle the claims of Texas to New Mexican territory. The Texan threats to use force he treated with cavalier indifference, remarking that as long as New Mexico was a territory, and therefore belonged to the United States, any controversy with her was a controversy with the federal government, which would know how to play her part by "defending her territory from invasion, and her people from violence,"—a hint that had a salutary effect upon the Texans; in fact the disunionists, generally, were not apt to do much more than threaten while a Whig like Taylor was backed up by a Democrat like Benton. He also pointed out that it was not necessary, however desirable, to make a compact with Texas about the boundaries, as they could always be settled, whether she wished it or not, by a suit before the Supreme Court; and again intimated that a little show of firmness would remove all danger of a collision. "As to anything that Texas or New Mexico may do in taking or relinquishing possession, that is all moonshine. New Mexico is the property of the United States, and she cannot dispose of herself or any part of herself, nor can Texas take her or any part of her." He showed a thorough acquaintance with New Mexican geography and history, and alluded to the bills he had already brought in, in 1844 and 1850, to establish a divisional line between the territory and Texas, on the longitude first of one hundred and then of one hundred and two degrees. He recalled the fact that before the annexation of Texas, and in a bill proposing to settle all questions with her, he had inserted a provision forever prohibiting slavery in all parts of the annexed territory lying west of the hundredth degree of longitude. He also took the opportunity of formally stating his opposition to any form of slavery extension, remarking that it was no new idea with him, but dated from the time when in 1804, while a law student in Tennessee, he had studied Blackstone as edited by the learned Virginian, Judge Tucker, who, in an appendix, treated of, and totally condemned, black slavery in the United States. The very difficulty, or, as he deemed it, the impossibility, of getting rid of the evil, made Benton all the more determined in opposing its extension. "The incurability of the evil is the greatest objection to the extension of slavery. If it is wrong for the legislator to inflict an evil which can be cured, how much more to inflict one that is incurable, and against the will of the people who are to endure it forever! I quarrel with no one for deeming slavery a blessing; I deem it an evil, and would neither adopt it nor impose it on others." The solution of the problem of disposing of existent slavery, he confessed, seemed beyond human wisdom; but "there is a wisdom above human, and to that we must look. In the mean time, do not extend the evil." In justification of his position he quoted previous actions of Congress, done under the lead of Southern men, in refusing again and again, down to 1807, to allow slavery to be introduced into Indiana, when that community petitioned for it. He also repudiated strongly the whole spirit in which Clay had gotten up his compromise bill, stating that he did not believe in geographical parties; that he knew no North and no South, and utterly rejected any slavery compromises except those to be found in the Constitution. Altogether it was a great speech, and his opposition was one of the main causes of the defeat of Clay's measure.
Benton's position on the Wilmot Proviso is worth giving in his own words: "That measure was rejected again as heretofore, and by the votes of those who were opposed to extending slavery into the territories, because it was unnecessary and inoperative,—irritating to the Slave States, without benefit to the Free States, a mere work of supererogation, of which the fruit was discontent. It was rejected, not on the principle of non-intervention; not on the principle of leaving to the territories to do as they pleased on the question, but because there had been intervention; because Mexican law and constitution had intervened, had abolished slavery by law in those dominions; which law would remain in force until repealed by Congress. All that the opponents to the extension of slavery had to do, then, was to do nothing. And they did nothing."
Before California was admitted into the Union old Zachary Taylor had died, leaving behind him a name that will always be remembered among our people. He was neither a great statesman nor yet a great commander; but he was an able and gallant soldier, a loyal and upright public servant, and a most kindly, honest, and truthful man. His death was a greater loss to the country than perhaps the people ever knew.
The bill for the admission of California as a free state, heartily sustained by Benton, was made a test question by the Southern disunionists; but on this occasion they were thoroughly beaten. The great struggle was made over a proposition to limit the southern boundary of the state to the line of 36° 30', and to extend the Missouri line through to the Pacific, so as to authorize the existence of slavery in all the territory south of that latitude. This was defeated by a vote of thirty-two to twenty-four. Not only Benton, but also Spruance and Wales of Delaware, and Underwood of Kentucky, joined with the representatives from the Free States in opposing it. Had it not been for the action of these four slave-state senators in leaving their associates, the vote would have been a tie; and their courage and patriotism should be remembered. The bill was then passed by a vote of thirty-four to eighteen, two other Southern senators, Houston of Texas, and Bell of Tennessee, voting for it, in addition to the four already mentioned. After its passage, ten of the senators who had voted against it, including, of course, Jefferson Davis, and also Benton's own colleague from Missouri, Atchison, joined in a protest against what had been done, ending with a thinly veiled threat of disunion,—"dissolution of the confederacy," as they styled it. Benton stoutly and successfully opposed allowing this protest to be received or entered upon the journal, condemning it, with a frankness that very few of his fellow-senators would have dared to copy, as being sectional and disunion in form, and therefore unfit even for preservation on the records.
When the Fugitive Slave Act of 1850 was passed, through the help of some Northern votes, Benton refused to support it; and this was the last act of importance that he performed as United States Senator. He had risen and grown steadily all through his long term of service; and during its last period he did greater service to the nation than any of his fellow-senators. Compare his stand against the slavery extremists and disunionists, such as Calhoun, with the position of Webster at the time of his famous seventh of March speech, or with that of Clay when he brought in his compromise bill! In fact, as the times grew more troublesome, he grew steadily better able to do good work in them.
It is this fact of growth that especially marks his career. No other American statesman, except John Quincy Adams,—certainly neither of his great contemporaries, Webster and Clay,—kept doing continually better work throughout his term of public service, or showed himself able to rise to a higher level at the very end than at the beginning. Yet such was the case with Benton. He always rose to meet a really great emergency; and his services to the nation grew steadily in importance to the very close of his life. Whereas Webster and Clay passed their zenith and fell, he kept rising all the time.