than at the North, the attempt to add the Wilmot proviso to the territorial organization raised the Southern opposition to an intensity which it had not known before.  Fuel was added to the flame by the application of California, whose population had been enormously increased by the discovery of gold within her limits, for admission as a free State.  If New Mexico should do the same, as was probable, the Wilmot proviso would be practically in force throughout the best portion of the Mexican acquisition.  The two sections were now so strong and so determined that compromise of any kind was far more difficult than in 1820; and it was not easy to reconcile or compromise the southern demand that slavery should be permitted, and the northern demand that slavery should be forbidden, to enter the new territories.

In the meantime, the Presidential election of 1848 had come and gone.  It had been marked by the appearance of a new party, the Free Soilers, an event which was at first extremely embarrassing to the managers of both the Democratic and Whig parties.  On the one hand, the northern and southern sections of the Whig party had always been very loosely joined together, and the slender tie was endangered by the least admission of the slavery issue.  On the other hand, while the Democratic national organization had always been more perfect, its northern section had always been much more inclined to active anti-slavery work than the northern Whigs.  Its organ, the Democratic Review, habitually spoke of the slaves as “our black brethren”; and a long catalogue could be made of leaders like Chase, Hale, Wilmot, Bryant, and Leggett, whose democracy was broad enough to include the negro.  To both parties, therefore, the situation was extremely hazardous.  The Whigs had less to fear, but were able to resist less pressure.  The Democrats were more united, but were called upon to meet a greater danger.  In the end, the Whigs did nothing; their two sections drew further apart; and the Presidential election of 1852 only made it evident that the national Whig party was no longer in existence.  The Democratic managers evolved, as a solution of their problem, the new doctrine of “popular sovereignty,” which Calhoun re-baptized “squatter sovereignty.”  They asserted as the true Democratic doctrine, that the question of slavery or freedom was to be left for decision of the people of the territory itself.  To the mass of northern Democrats, this doctrine was taking enough to cover over the essential nature of the struggle; the more democratic leaders of the northern Democracy were driven off into the Free-Soil party; and Douglas, the champion of “popular sovereignty,” became the leading Democrat of the North.