The partisans of Reëlection dwell much on the position and character of Mr. Greeley, insisting that he cannot be trusted in the Presidency,--partly because helped into power by Democrats, and partly from an alleged want of stability. It is difficult to hear these barefaced allegations, in utter disregard of the prodigious testimony afforded by his long career, without wonder at the extent to which prejudice and invention can be carried. Had he been presented at Philadelphia with the saving sanction of a regular nomination, the same partisans who now seek to exhibit him as a tool or an imbecile would dwell with pride on his eminent qualities, making him, by the side of his competitor, an angel of light. Knowing them both, his superiority I may affirm. To say that under him Slavery can in any way be revived, or that the Rebel debt or the pension of Rebel soldiers or compensation for slaves can find favor, or that the equal rights of the freedmen, to which he is so solemnly pledged, can in any way be impaired,--all this is simply atrocious. Nothing of the kind can be done without violation of the Constitution as amended,--not to speak of the departure from that rule of life which he has ever followed. There is no Democrat sympathizing with his nomination who would not spurn the infamous treachery. I dismiss the whole partisan extravagance to the contempt it deserves. The imputation that his election will be the return to power of the old Democratic party is much like saying that he will cease to be himself, and that his surpassing individuality, making him so conspicuous, will be lost. They who make the imputation forget that this old party, if it has not ceased to exist, is changed in character. Standing on a Republican platform, and with a Republican candidate, it may look the Republican party in the face, claiming for itself the Future, if not the Past. Plainly it is not that Democratic party against which Republicans have contended. If Democrats have influence with Horace Greeley, it will be because they have sincerely placed themselves by his side on a platform which distinctly announces all that Republicans have ever claimed. Against all pretended distrust I oppose the open record of his life. By this let him be judged. And here it will be observed, that, while sometimes differing from others in methods, he has never, at any moment, ceased to be a champion, being always the same. Here is a private letter, which has only recently appeared, being a gleam of sunlight from his soul, which the dark days of the war could not quench:-- OFFICE OF THE TRIBUNE, NEW YORK, June 26, 1863.