Before the Wilmot proviso was interposed, the abolition of slavery in the District of Columbia had been the chief theme of agitation. Petitions for this purpose, by thousands, poured into Congress, session after session. The rights and the wishes of the owners of slaves within the District were boldly disregarded. Slavery was denounced as a national disgrace, which the laws of God and the laws of men ought to abolish, cost what it might. It mattered not to the fanatics that the abolition of slavery in the District would convert it into a citadel, in the midst of two slaveholding States, from which the Abolitionist could securely scatter arrows, firebrands and death all around. It mattered not with them that the abolition of slavery in the District would be a violation of the spirit of the Constitution and of the implied faith pledged to Maryland and Virginia, because the whole world knows that those States would never have ceded it to the Union, had they imagined it could ever be converted by Congress into a place from which their domestic peace and security might be assailed by fanatics and Abolitionists. Nay, the Abolitionists went even still further. They agitated for the purpose of abolishing slavery in the forts, arsenals and navy-yards which the Southern States had ceded to the Union, under the Constitution, for the protection and defence of the country. Thus stood the question when the Wilmot proviso was interposed, to add fuel to the flame, and to excite the Southern people to madness. . . . . . . . . It would be the extreme of dangerous infatuation to suppose that the Union was not then in serious danger. Had the Wilmot proviso become a law, or had slavery been abolished in the District of Columbia, nothing short of a special interposition of Divine Providence could have prevented the secession of most, if not all, the slaveholding States. It was from this great and glorious old Commonwealth, rightly denominated the ‘Keystone of the Arch,‘ that the first ray of light emanated to dispel the gloom. She stands now as the days-man, between the North and the South, and can lay her hand on either party, and say, thus far shalt thou go, and no farther. The wisdom, moderation and firmness of her people qualify her eminently to act as the just and equitable umpire between the extremes.