It seems to me that no man who knows our history, who understands truly the genius of our people, and who understands also the principles upon which the Union and the Constitution are based, can fail to believe that it is not by the conflict of sectional parties and their triumph, but by the defeat of sectional parties by a stronger and more patriotic national party, that the divided house can be reconciled and the house itself made to stand in safety. The safety of the Union depends upon maintaining the Federal government in the hands of a national party, which shall carry out the spirit of the Federal Constitution. A solemn responsibility rests upon every citizen in this regard. I propose then to inquire-- 1st--What is the true spirit of the Constitution, and what the true policy of the Federal government on the subject of slavery? and, 2d--How do the parties and the candidates now before the people stand in regard to it? I wish distinctly to say that I do not propose to consider the question of slavery in its moral or religious aspects, but as a political question under the Federal Constitution. As to my personal opinion in regard to slavery, I am free to say I consider it an evil, which I hope will be eradicated from the earth, but I do not regard it as the greatest of evils, nor do I consider that it requires political action from the Federal government. On the contrary, I believe that while the question of slavery might be safely agitated, with a view to political action, in a consolidated or imperial government, or even in an American Federal State, it cannot under our Federal system of government be safely or rightly agitated as a national question. Its agitation as such has done more to alienate and embitter the two sections of our Union--more to rouse the spirit of slavery aggression and extension, and to tighten the bonds and increase the burdens of the slave, than it has done to effect emancipation. Slavery is an evil permitted by Providence for ends that time will reveal. From this form of social evil, he is still educing good, far more good to the slaves, as a class, than to the masters as a class. It must not be suddenly nor rashly dealt with. Like a disease that pervades the blood or the whole constitution of a man, it needs not, for it cannot be reached by, the exterminating knife or cautery of the surgeon; it requires the gradual, purifying and alterative influences of gentle medicines, that work their way almost imperceptibly to the very principle and seat of the malady. For my part, while I yield to no man in my love of liberty and the rights of man, I frankly say I had rather that the "rivulet of African slavery" flow on for five hundred years to come, than to see around me the fragments of a dissevered Union. In that Union, and the silent steady workings of its glorious principles, more than in the conflict of antagonist and angry parties, rest the hopes, not alone of African emancipation, but of unborn nations.