He chaired the Senate Foreign Relations Committee from 1861 to 1871, until he lost the position following a dispute with President Ulysses S. Grant over the attempted annexation of Santo Domingo.

Sumner had a controversial and divisive legacy for many years after his death, but in recent decades, his historical reputation has improved in recognition of his early support for racial equality.

His father, Charles Pinckney Sumner, was a Harvard-educated lawyer, abolitionist, and early proponent of racial integration of schools, who shocked 19th-century Boston by opposing anti-miscegenation laws.

Expanding on Channing's argument that human beings had infinite potential to improve themselves, Sumner concluded that environment had "an important, if not controlling influence" in shaping people.

[22] Sumner embarked on a public political career in 1845, when he emerged as one of the most prominent critics of slavery in the city of Boston and the state of Massachusetts, a hotbed of abolitionist sentiment.

Arguing before the Massachusetts Supreme Court, Sumner noted that schools for blacks were physically inferior and that segregation bred harmful psychological and sociological effects—arguments made in Brown v. Board of Education over a century later.

The impasse was broken after three months and Sumner was elected on a parliamentary technicality by a one-vote majority on April 24, 1851, in part thanks to the support of Senate President Henry Wilson.

I was so excited I pitched about like a mad woman, shouted, waved, hung onto fences, rushed thro crowds, and swarmed about in a state of rapterous insanity till it was all over and then I went home hoarse and worn out."

Historian William Gienapp has concluded that Brooks's "assault was of critical importance in transforming the struggling Republican party into a major political force.

In his eyes, the speech was "a gauntlet thrown down, a challenge to the 'Slave Power' to admit once and for all that it were encircling the free states with their tentacular grip and gradually siphoning off the breath of democracy-loving citizens.

The Massachusetts General Court reelected him in November 1856, believing that his vacant chair in the Senate chamber served as a powerful symbol of free speech and resistance to slavery.

Though fellow Republicans advised a less strident tone, he answered: "When crime and criminals are thrust before us, they are to be met by all the energies that God has given us by argument, scorn, sarcasm and denunciation."

He attacked attempts to depict slavery as a benevolent institution, said it stifled economic development in the South, and that it left slaveholders reliant on "the bludgeon, the revolver, and the bowie-knife".

[46] After the fall of Fort Sumter in April 1861, Sumner, Chandler and Wade repeatedly visited President Abraham Lincoln at the White House to discuss slavery and the rebellion.

[46] Gilbert Osofsky argues that Sumner saw the war as a "death struggle" between "two mutually contradictory civilizations," and his solution was "to 'civilize' and 'Americanize' the South" by conquest, then forcibly mold it into a society defined in Northern terms, as an idealized version of New England.

[50] He believed that military necessity would eventually force Lincoln's hand and that emancipation would give the Union higher moral standing, which would keep Britain from entering the Civil War on the Confederacy's side.

[50][46] In October 1861, at the Massachusetts Republican Convention in Worcester, Sumner openly expressed his belief that slavery was the war's sole cause and that the Union government's primary objective was to end it.

[50] Conservative Massachusetts newspapers editorialized that he was mentally ill and a "candidate for the insane asylum,"[50] but the Radicals fully endorsed Sumner's speech, and he continued to advance his argument publicly.

Sumner's radical legal theory of Reconstruction proposed that nothing beyond the confines of the Constitution, read in light of the Declaration of Independence, restricted Congress's treatment of the rebelling states.

In a three-hour speech, Sumner spoke in favor of the treaty on the Senate floor, describing in detail Alaska's imperial history, natural resources, population, and climate.

[70] This proposition offended many Britons, but was taken seriously by many Americans, including the Secretary of State, whose support for it nearly derailed the settlement with Great Britain in the months before the arbitration conference met at Geneva.

Grant believed that the island's mineral resources would be valuable to the United States, and that African Americans repressed in the South would have a safe haven to which to migrate.

In December 1870, still fearful that Grant meant to acquire Santo Domingo somehow, Sumner gave a fiercely critical speech accusing him of usurpation and Babcock of unethical conduct.

The Liberal Republicans supported black suffrage, the three Reconstruction amendments, and the basic civil rights already protected by law, but also called for amnesty for ex-Confederates and decried the Republican governments in the South elected with the help of black votes, belittled the terrorism of the Ku Klux Klan, and argued that the time had come to restore "home rule" in the South, which in practical terms meant white Democratic rule.

[90] Long ailing, Charles Sumner died of a heart attack at his home in Washington, D.C., on March 11, 1874, aged 63, after serving nearly 23 years in the Senate.

At his March 16 burial in Mount Auburn Cemetery in Cambridge, Massachusetts, the pallbearers included Henry Wadsworth Longfellow, Oliver Wendell Holmes, Ralph Waldo Emerson, and John Greenleaf Whittier.

Sumner's reputation among historians in the first half of the 20th century was largely negative—he was particularly blamed by both the Dunning School and anti-Dunning revisionists for the excesses of Radical Reconstruction, which, in the prevailing scholarship, included letting Blacks vote and hold office.

[54] Modern scholars have emphasized his role as a foremost champion of Black rights before, during, and after the Civil War; one historian says he was "perhaps the least racist man in America in his day.

From the time he entered public life till he died he was a strong force constantly working for righteousness….To Sumner more than to any single man, except possibly Lincoln, the colored race owes its emancipation and such measure of equal rights as it now enjoys.

Carving out a reputation as the South's most hated foe and the Negro's bravest friend, he inflamed sectional differences, advanced his personal fortunes, and helped bring about national tragedy.