In 1846-47 Sumner made several speeches in favor of the Whig party adopting an anti slavery attitude. He wrote for the newspapers against the Mexican War; declared that it was 'unconstitutional, unjust and detestable, op posed further expenditures for it, called for the withdrawal of troops and opposed the open ing of the territory to he acquired from Mex ico to slavery. He joined the Free Soil party of 1848 and was nominated for Congress in October, but failed of election. When Web ster, in his speech of 7 March 1850, refused to vote to exclude slavery from California and New Mexico, he became, in the eyes of many in Massachusetts, an apologist of slavery and this situation opened the door of the Senate to Sumner.
In Massachusetts the autumn campaign hinged on the question whether the State should ap prove the Compromise of 1850 and the course of Webster in supporting it. There was bitter opposition to the Fugitive Slave Law and the manner of its enforcement. Sumner made an important speech in Faneuil Hall 6 November against the Fugitive Slave law and demanded its repeal. This speech made possible his elec tion as senator in January 1851, for in the State election the combined Democrats and Free Soilers had a majority of the legislature and chose Sumner rather than Winthrop, the Whig candidate, as senator. • With the entrance of Sumner into the Sen ate in December 1851 a new force for anti slavery agitation was present. He was an uncompromising, fiery, earnest and. persistent antagonist of slavery. He was the spokesman of the anti-slavery forces in the Senate as Calhoun had been for the pro-slavery interests. Although the leaders of both parties were for peace, Clay and Webster on one side and Cass, Buchanan and Douglas on the other, never theless Sumner believed that the Compromise of 1850 was wrong and that °nothing can be settled which is not right.* It was not until August 1852, after both the Whig and Demo cratic National Conventions had declared their support of the Compromise of 1850, that Sum ner spoke of the great question, viz., °Freedom National, Slavery Sectional.* His argument was to the effect that slavery was not recog nized in the Constitution, that Congress had no power to establish it and that, therefore, it could not legally exist where thejurisdiction of the national government was exclusive; that the Fugitive Slave Law was unconstitutional and, therefore, should not be obeyed. This
speech made Sumner the leader of the anti slavery party and his doctrines were accepted as sound by its rank and file.
The next Congress, that commencing 5 Dec. 1853, was made famous by the passage of the Kansas-Nebraska Bill, which was de signed to repeal the Missouri Compromise. It was on 23 Jan. 1854 that Senator Douglas in troduced a bill dividing the Nebraska Terri tory into Kansas and Nebraska. This bill de dared that the Missouri Compromise "was superseded on the principle of the legislation of 1850, commonly called the compromise measure, and is hereby declared in operation.* Sumner spoke against the bill 15 Feb. 1854 and declared that the Missouri Compromise was a binding contract. His speech on 26 June in reply to an attack on Boston and Massachusetts by Southern senators, particularly Senators Butler of South Carolina and Mason of Vir ginia, aroused great feeling.
The passage of the Kansas-Nebraska Act led to the formation of the Republican party. A Republican convention, composed mostly of Free Soldiers, was held at Worcester, Mass., 7 Sept. 1854 and Sumner spoke for the new party. He advocated resistance to the enforce ment of the Fugitive Slave Law and advised the passage of personal liberty laws to nullify its workings. He justified his position by denying that the provision of the Constitution touching the rendition of °persons held to service or labor,* conferred any power on the national government to establish uniform rules for the rendition of fugitives*; that therefore, each State had the right to determine for itself the extent of the obligation assumed. In consequence the Fugitive Slave Law was un constitutional and the States had a right to act so as to secure for their citizens claimed as fugitive slaves the right of trial by jury and the privilege of habeas corpus. This view would give the States liberty to construe the Con stitution and pass laws which their construc tion of the Constitution permitted. In case there was a conflict between the Supreme Court and the States in the construction of the Con stitution, then no man °will voluntarily aid in enforcing a judgment which in conscience he believed wrong.* This was preaching revo lutionary doctrine and was the most violent and extreme position which Sumner had taken up to this date.