Webster, Clay, Calhoun, John Quincy Adams, not to mention others, all died near the middle of the century, and their political power passed to younger men.

Adams gave his blessing to a young friend and co-laborer, William H.Seward of New York, intimating that he expected him to do much to curb the threatening power of the slaveholding oligarchy; while Andrew Jackson, who died earlier, had already conferred a like distinction upon young Stephen A.Douglas.
There was no lack of aspirants for the fallen mantles.
John C.Calhoun continued almost to the day of his death to modify his interpretation of the Constitution in the interest of his section.

As a young man he avowed protectionist principles.

Becoming convinced that slave labor was not suited to manufacture, he urged South Carolina to declare the protective tariff laws null and void within her limits.
When his section seemed endangered by the distribution of anti-slavery literature through the mail, he extemporized a theory that each State had a right to pass statutes to protect itself in such an emergency, in which case it became the duty of the general Government and of all other States to respect such laws.

When it finally appeared that the territory acquired from Mexico was likely to remain free, the same statesman made further discoveries.