1850–51 Massachusetts gubernatorial election

In 1848, the new abolitionist and pro-labor Free Soil Party, which drew support from both Whigs and Democrats and members of the Liberty Party, was founded. Whig George N. Briggs won the 1848 and 1849 elections with a plurality of the popular vote. As no candidate received a majority in either race, it was the majority-Whig legislature that returned Briggs to office each time. In their respective 1849 conventions, Democrats embraced anti-slavery resolutions and the Free Soilers adopting reformist planks on state issues, though a formal anti-Whig alliance was precluded by their differences on national issues.[2]

In 1850, the United States Congress passed the Fugitive Slave Act and Compromise of 1850, increasing anti-slavery agitation in Massachusetts and energizing opposition to the remaining Whigs, who tended to be conservatives who either reconciled with the institution of slavery or as textile manufacturers even directly profited from cheap cotton and in turn, slave labor.[3][4]

During his failed campaign for Governor in 1849, Democratic nominee George S. Boutwell became acquainted with Free Soil Party leaders Charles Sumner and Henry Wilson.[5] Despite opposition from hardline members of their parties, the leaders resolved to form an alliance to unseat the Whig establishment.[4] As part of this agreement, Free Soilers agreed to support Boutwell for Governor and fellow Democrat Nathaniel Prentice Banks for Speaker of the Massachusetts House, while Sumner would be elected U.S. Senator and Wilson would become President of the Massachusetts Senate.[6] Both parties would run a unified legislative ticket but continue to run opposing tickets for federal and local office.[7]

The coalition agreement met opposition from some more conservative ex-Whig Free Soilers, such as Charles Francis Adams, Samuel Hoar, Richard Henry Dana Jr., John Palfrey, and gubernatorial nominee Stephen Clarendon Phillips, all of whom preferred a narrow anti-slavery focus. These men either outright opposed the Democratic reform agenda or argued that it distracted from that mission.[8]

The Massachusetts House of Representatives certified the popular returns on January 12. The House voted to nominate Boutwell and Phillips for consideration by the Senate. On the first House ballot, Boutwell defeated Briggs 218–171. On the second, Phillips defeated Briggs 216–170. In the Massachusetts State Senate, Boutwell was elected unanimously with 32 votes with three blanks.[11]

Upon their entry to office and apportionment of state offices, the coalition faced heavy blowback. Future U.S. Supreme Court Justice Benjamin R. Curtis, then the president of the Massachusetts Bar Association, circulated a letter calling for criminal conspiracy charges against Sumner, Wilson, and Boutwell; most Whig legislators signed the letter, but the party declined to call for the election to be overturned.[9]

Wilson and Banks were also elevated to Speaker and Senate President, but Sumner's election to the U.S. Senate was far more contentious due to opposition by conservative Democrats led by former Whig Caleb Cushing,[12] who joined with the Whig minority.[6] The election took several months to reach a conclusion, with Sumner prevailing by only one vote in the House. Sumner blamed Boutwell's failure to intercede for his difficulty and would continue to blame Boutwell for the coalition's eventual collapse.[13]

• 1850 Massachusetts legislature