He returned to his law practice poor in pocket but rich in the possession of lifelong friendships and happy memories.
Sumner's political career did not begin until 1847, when as a Whig he not only opposed any further extension of slavery but strove to commit his party to the policy of emancipation in all the States.

Failing in this attempt, Sumner became an active Free-Boiler in 1848.

He was twice a candidate for Congress on the Free-soil ticket but failed of election.
In 1851 he was elected to the United States Senate by a coalition between his party and the Democrats.

This is the only public office he ever held, but he was continuously reelected until his death in 1874.
John Quincy Adams had addressed audiences trained in the old school, which did not defend slavery on moral grounds.

Charles Sumner faced audiences of the new school, which upheld the institution as a righteous moral order.