At the present day it is plain that a revolution, neither slow nor silent, is taking place in the political parties of America. The occasion thereof is the nomination of a man for the presidency who has no political or civil experience, but who has three qualities that are important in the eyes of the leading men who have supported and pushed him forward: one is, that he is an eminent slaveholder, whose interests and accordingly whose ideas are identical with those of the slaveholders; the next, that he is not hostile to the doctrines of northern manufacturers respecting a protective tariff; and the third, that he is an eminent and very successful military commander. The last is an accidental quality, and it is not to be supposed that the intelligent and influential men at the North and South who have promoted his election, value him any more on that account, or think that mere military success fits him for his high office, and enables him to settle the complicated difficulties of a modern State. They must know better; but they must have known that many men of little intelligence are so taken with military glory that they will ask for no more in their hero; it was foreseen, also, that honest and intelligent men of all parties would give him their vote because he had never been mixed up with the intrigues of political life. Thus "far-sighted" politicians of the North and South saw that he might be fairly elected, and then might serve the purposes of the slaveholder, or the manufacturer of the North. The military success of General Taylor, an accidental merit, was only the occasion of his nomination by the whigs; his substantial merit was found in the fact, that he was supposed, or known, to be favorable to the "peculiar institution" of the South, and the protective policy of the manufacturers at the North: this was the cause of his formal nomination by the Whig Convention of Philadelphia, and his real nomination by members of the whig party at Washington. The men of property at the South wanted an extension of slavery; the men of property at the North, a high protective tariff; and it was thought General Taylor could serve both purposes, and promote the interests of the North and South. Such is the occasion of the revolution in political parties: the cause is the introduction of a new idea into these parties entirely hostile to some of their former doctrines. In the electioneering contest, the new idea was represented by the words "Free Soil." For present practice it takes a negative form: "No more Slave States, no more Slave Territory," is the motto. But these words and this motto do not adequately represent the idea, only so much thereof as has been needful in the present crisis.