His sustained support for President Ulysses S. Grant's administration despite allegations of corruption lost him the backing of reformers, and his legal arguments in favor of Democratic candidate Samuel J. Tilden in the disputed presidential election of 1876 outraged many Republicans.

Grandson Merritt displayed intelligence and oratorical talents at an early age, impressing people with his abilities to recite Cicero and exhort at religious revivals.

He was dissatisfied with the limits of Moretown, and left home to live and study law under the tutelage of family friend (and future Vermont governor) Paul Dillingham in nearby Waterbury.

[5] After reading that the territory of Wisconsin had passed its constitution and was soon to become a state, Carpenter chose to migrate west and begin his career as a lawyer in Beloit on the endorsement of that spot by the New England Emigrating Society's Dr. Horace C. White.

[7] Despite an earlier warning from Choate to steer clear of politics, Carpenter successfully ran for Rock County district attorney, serving from 1850 to 1852 and 1854 to 1856.

[16] Carpenter supported Democrat Stephen Douglas in the 1860 presidential election, viewing Republican Abraham Lincoln as an honest but incompetent sectional candidate.

[18] While he saw that many federal actions would be unconstitutional in peacetime, he reasoned that arbitrary arrests and suspensions of habeas corpus were acts of self-preservation during wartime and thereby permitted.

[21] Personal letters he had written saying Lincoln was "idiotic" found their way into newspapers, but Carpenter supported him for re-election in 1864 by making numerous pro-Union and pro-Lincoln speeches.

[22] Carpenter was the key attorney in a series of landmark cases before the U.S. Supreme Court which helped define states' rights by determining the legality of the Reconstruction acts passed by Congress.

Ex parte Garland dealt with the disbarment from federal courts of Southern lawyers who refused to take an oath swearing they had not taken up arms or assisted the Confederacy.

Carpenter argued that the act passed on January 24, 1865, was ex post facto (the war had since ended) and a bill of attainder (it punished without a trial).

Confederate Colonel William H. McCardle, the editor of the Vicksburg Times, was charged with defying military authority by inciting rebellion, libeling federal officials, and intimidating voters.

Rather than claiming the Union's "right of conquest," Carpenter said the Southern states had surrendered their constitutional protections when they had seceded, essentially reverting to territories.

Butchers and cattle dealers thrown out of work by the law obtained an injunction from a district court, claiming they had been denied equal protection under the Fourteenth Amendment and deprived of property under the due process clause.

He called for the enfranchisement of African-American men and invited members of the Loyal Democracy to join the Republicans, as he himself did in the summer of 1867 with his support for Governor Lucius Fairchild's re-election.

With high-profile backing Carpenter ran successfully for the senate seat occupied by James R. Doolittle, a "Johnsonized" Republican who had fallen out of favor with his party.

[30] After Rublee was appointed minister to Switzerland by President Grant, Keyes became party chairman and closely coordinated with Carpenter to distribute federal patronage jobs to political allies.

As part of another committee inquiry, Carpenter went to Louisiana to investigate election claims in order to determine the rightful governor of the contested state.

[39] Opposition newspapers like the New York Tribune responded by not only criticizing Carpenter's methods, but by also condemning his moral character by bringing his private life into question.

[40] Later in his term editors accused Carpenter of trying to effectively "gag" newspapers by advancing a bill that would allow judicial process to be served upon the agents (i.e. interviewers) of persons involved in civil suits.

In a spirit of reform he boldly owned up to administration excesses such as the Credit Mobilier and the "Salary Grab," defending them in a speech in Janesville.

[45] In 1875 Carpenter was implicated in the Whiskey Ring scandal that funneled federal liquor tax revenues to some states' Republican parties.

[46] During this time Carpenter, along with Jeremiah S. Black and Montgomery Blair, was also defending Grant's Secretary of War William W. Belknap against charges that he had accepted money in exchange for the appointment of a post trader.

[48] Also in 1875 Carpenter was defense counsel for officials of the Miners’ National Association (MNA) in an important labor case that sought to apply the legal concept of conspiracy to union picketing and organization efforts.

The case grew out of a coal miners' strike in Clearfield County, Pennsylvania, which was supported by the MNA, then numerically one of the largest American trade unions.

First over fifty of the striking workers were tried upon a charge of criminal conspiracy and thirty-six of them were convicted with some sentenced to jail, although they appeared to have been guilty of no more than peaceful picketing.

[49] Following the disputed presidential election of 1876, Carpenter was hired by supporters of the Democratic candidate Samuel J. Tilden to examine Louisiana's vote counts and argue for victory over Republican Rutherford B. Hayes.

[50] Despite ongoing press criticism and declining health, in 1878 Carpenter launched a bid for the senate seat occupied by Republican Timothy Howe.