A “Constitutional Union,” really an American Convention, had met at Baltimore on the 9th of May. Twenty States were represented, and John Bell, of Tennessee, and Edward Everett, of Massachusetts, were named for the Presidency and Vice-Presidency. Their friends, though known to be less in number than either those of Douglas, Lincoln or Breckinridge, yet made a vigorous canvass in the hope that the election would be thrown into the House, and that there a compromise in the vote by States would naturally turn toward their candidates. The result of the great contest is elsewhere given in our Tabulated History of Politics. THE PRINCIPLES INVOLVED. Lincoln received large majorities in nearly all of the free States, his popular vote being 1,866,452; electoral vote, 180. Douglas was next in the popular estimate, receiving 1,375,157 votes, with but 12 electors. Breckinridge had 847,953 votes, with 76 electors; Bell, with 570,631 votes, had 39 electors. The principles involved in the controversy are given at length in the Book of Platforms, and were briefly these: The Republican party asserted that slavery should not be extended to the territories; that it could exist only by virtue of local and positive law; that freedom was national; that slavery was morally wrong, and the nation should at least anticipate its gradual extinction. The Douglas wing of the Democratic party adhered to the doctrine of popular sovereignty, and claimed that in its exercise in the territories they were indifferent whether slavery was voted up or down. The Breckinridge wing of the Democratic party asserted both the moral and legal right to hold slaves, and to carry them to the territories, and that no power save the national constitution could prohibit or interfere with it outside of State lines. The Americans supporting Bell, adhered to their peculiar doctrines touching emigration and naturalization, but had abandoned, in most of the States, the secrecy and oaths of the Know-Nothing order. They were evasive and non-committal on the slavery question. Preparing for Secession.