The succession of days and years and centuries is noted in calendars; but it is great events, constituting historical epochs, that mark the progress and destiny of our race. Decisive battles, vast reforms, civil or religious, great scientific discoveries or mechanical inventions, dynastic changes, political revolutions, the union or dismemberment of states, the birth or death of republics, the rise or fall of empires--these are the deep notches in the groove of time, the mighty landmarks in the pathway of humanity. It is the fate of the American Union, involving the liberty of our country and mankind, that is to be decided in our approaching Presidential election. How paltry are all party questions in the presence of an issue so transcendent as this! How dare we mingle old party names or conflicts with such a question, when the life of the Union is trembling in the balance! The maintenance of the Union is the one majestic question, and the _Union party_, in name, and in fact, is the only one that should exist, until this great issue is decided. Then, when the Union is rescued from present and future peril, we may exhume the past, use old party names, or discuss old party issues, but until then to unfold a party banner, and revive old party prejudices, is treason to our country and mankind. It is not Democrats alone, or Republicans alone, as separate parties marshalled against each other, that can save the Union. During this straggle for the Union, we do not hear of Democratic or Republican admirals or generals, divisions or regiments; no, we have only one great Union army, discarding all party names or symbols, and fighting only for and under the banner of the Union. It is then a grave objection to the Chicago McClellan Convention, that, in such a crisis as this, it summoned only a _Democratic_ Convention, and appealed only to the _Democratic_ party to save the Government. As well might we summon only a Democratic army to fight the battles of our country, as conduct such an election as this under any old party name and banner. Thousands of Republicans as well as Democrats, together, under the banner of the Union, fight now the battles of their country. Thousands of Republican as well as Democratic soldiers sleep in their bloody shrouds, or lie wounded on beds of agony; but who dare ask to what party they belonged? It was an unholy ambition, stimulated by party leaders, a thirst for office and emoluments, that rallied under an old party name at Chicago, when the whole people should have been summoned to the rescue.