It is astonishing to me that men who profess the sentiments expressed by conservative men of the Republican party, if they are sincere in their desire that slavery should die out, should fail to see that the compromise of 1850 and the Kansas and Nebraska law are alike based upon the only principle by which the ultimate extinction of slavery on this continent must take place. All that freedom needed, and all that it could constitutionally claim, was the withdrawal of the national intervention in favor of slavery, which intervention existed so long as a geographical line marked out by Congress existed over the national domain to separate Free and Slave States; and the leaving of the question of slavery to the local legislatures; by them only had it been or could it be created, and by them only had it been or could it be abolished. When the national territory was made free by the law of non-intervention, slavery was left entirely to the local law, and as freedom is the rule and slavery the exception, the chances were three to one in favor of free institutions in every new State. And yet it is for bringing the slavery agitation to this result--a result of which the men of the South upon their own principles cannot complain, and of which their best men do not complain, and of which the North has no reason to complain, but rather to rejoice, that Stephen A. Douglas, the ablest statesman of whom this nation can boast since the mighty intellect of Webster ceased to speak in words of power, has been covered all over with the vilest and bitterest denunciation--denunciation that would seem to be more the outpouring of personal malignity than the voice of mere partisan hostility. It is for this result that Douglas has been outlawed by a professedly Democratic administration, and the Democratic party itself broken up by Southern disunionists, aided by that same administration. BUT A NATION'S RETURNING JUSTICE WILL YET LIFT ALOFT HER SCALE, AND STEPHEN A. DOUGLAS CAN AFFORD TO ABIDE HIS TIME. I have thus, I fear tediously to you, brought you to the last act of the great national drama of slavery agitation. Let us now briefly review the ground, sum up the points, and see how we stand for the final struggle near at hand. These are the propositions I have aimed to establish: 1. Slavery existed in all the States of the Union when it was formed, and no power was conceded to Congress, under the Confederation to interfere with it. 2. The Jefferson ordinance of 1784, the first act of Congress relating to the territory of the United States, conceded to the people of the territories as inchoate States, full power of internal legislation, and did not prohibit slavery.