The politics of Vermont encompass the acts of the elected legislative bodies of the US state, the actions of its governors, as overseen by the Vermont courts, and the acts of the political parties that vie for elective power within the state. The state's politics include local Democratic and Republican political parties, as well as several smaller parties.

Vermont's constitution, which was drafted in 1777 when Vermont became an independent republic, reflects the concerns of a sovereign state; it prohibited adult slavery except in certain limited circumstances and provided for universal male suffrage and public schools. These provisions were carried over to the state Constitution when Vermont joined the Union in 1791. Vermont has been a pioneer in legislation pertaining to land use, gay rights, and school funding. Between 1854 and 1962, the state always voted Republican for Governor, thereafter, the governor's office alternated between the Democratic and Republican parties. The legislature has been primarily Democratic since the mid-1980s.

In 1854, the Vermont delegation, consisting of three congressmen and two senators, vigorously, but unsuccessfully opposed the repeal of the Missouri Compromise in the U.S. Congress. The replacement act appeared to extend slavery.

From the founding of the Republican Party in the 1850s until the 1960s, only Republicans won general elections for Vermont's statewide offices. One method that made this possible was imposition of the "Mountain Rule." Under the provisions of the Mountain Rule, one U.S. Senator was a resident of the east side of the Green Mountains and one resided on the west side, and the governorship and lieutenant governorship alternated between residents of the east and west side. Nominees for Governor and Lieutenant Governor were allowed two one-year terms and, later, one two-year term. For nearly 100 years, likely Republican candidates for office in Vermont agreed to abide by the Mountain Rule in the interests of party unity. Several factors led to the eventual weakening of the Mountain Rule, including: the long time political dispute between the Proctor (conservative) and Aiken–Gibson (liberal) wings of the party; primaries rather than conventions to select nominees; the direct election of U.S. Senators; and several active third parties, including the Progressives, the Prohibition Party, and the Local Option movement. In the 1960s, the rise of the Vermont Democratic Party and the construction of Interstate 89 also contributed to the end of the Mountain Rule. Though I-89 is a north–south route, it traverses Vermont from east to west and changed the way Vermonters viewed how the state was divided.Newspaper article, The Mountain Rule in Vermont , New York Times, February 12, 1895Magazine article, Mountain Rule Revisited , by Samuel B. Hand, Vermont History Magazine, published by Vermont Historical Society, Summer/Fall 2003, pages 139 to 151

History Pre-Civil War In 1798, the Federalist controlled Vermont General Assembly declined to reelect Democratic-Republican Party judicial officials, including Chief Justice Israel Smith, which was later referred to as the Vergennes Slaughter. The Democratic-Republicans gained control over the governorship for the first time following Smith's victory in the 1807 election. However, opposition to the Embargo Act of 1807 resulted in the Federalists regaining control over the governorship and three of Vermont's four seats in the United States House of Representatives in 1808, although the Democratic-Republicans retained control over the state legislature.

In 1810, a new county was created by the legislature and was named after Thomas Jefferson by the Democratic-Republican controlled legislature, but renamed after George Washington by the Federalists in 1814.

Federalist U.S. Representative Martin Chittenden was the only member of Vermont's congressional delegation to oppose the United States declaration of war on the United Kingdom starting the War of 1812. Chittenden defeated Jonas Galusha in the 1813 gubernatorial election as the legislature voted 112–111 to select him as governor despite losing the popular vote. Chittenden attempted to withdraw the third brigade of Vermont's militia from the war on November 10, 1813, but it refused to follow his commands.

Chittenden won a plurality in the 1814 gubernatorial election and was selected by the legislature. The congressional election laws of Vermont was altered by the Democratic-Republicans in 1812 to be statewide in the hope that it would increase their amount of seats, but the Federalists won all six seats in 1814, and Isaac Tichenor was appointed to the United States Senate. The Federalists removed Chief Justice Royall Tyler from the supreme court and replaced him with Nathaniel Chipman.

The Vermont Federalists declined to participate in the Hartford Convention. The Federalists lost the governorship and legislature in 1815, and ran their last gubernatorial candidate in the 1817 election.

Vermont supported John Quincy Adams during the 1824 and 1828 presidential elections, with Andrew Jackson failing to win any counties in the 1828 election. The Anti-Masonic Party gained the governorship in the 1831 election and its presidential candidate William Wirt won Vermont in the 1832 election.

None of the candidates in the 1835 gubernatorial election received a majority of the popular vote and the legislature was unable to select a winner after thirty-five ballots. Lieutenant Governor Silas H. Jennison was instead selected to serve as acting governor. A constitutional amendment was passed in 1836, which abolished the Governor's Council and established the Vermont Senate.

Eight of the gubernatorial elections between 1836 and 1853 were decided by the legislature. From 1835 to 1855, the Whig Party won every gubernatorial election except for the Democratic victory in the 1853 election. The legislature elected Democratic nominee John S. Robinson was elected in 1853 after 20 ballots and a speaker after 31 ballots, but was unable to select an U.S. Senator.

The prohibition of alcohol was instituted through a referendum in 1852.

Slavery The legislature voiced its opposition to the Missouri Compromise in 1818, stating that "the right to introduce and establish slavery in a free government does not exist". The legislature passed a resolution in opposition of the annexation of Texas. Vermont's entire congressional delegation voted against the Kansas–Nebraska Act.

The Vermont Whigs adopted anti-slavery positions in 1842 to prevent themselves from losing more votes to the Liberty Party. William Slade, one of the leaders of the anti-slavery faction, was elected to the governorship in 1844. Slade left the Whigs in protest of the presidential nomination of Zachary Taylor, a slave-owner, and joined the Free Soil Party.

Post-Civil War The Vermont Republican Party was founded in 1854, and dominated politics in Vermont until the mid-20th century. An informal governing rule, the mountain rule, resulted in offices being shared between residents of eastern and western Vermont.

Term limits for statewide offices and the legislature were increased from one year to two years by a constitutional convention in 1870, and this convention also abolished the Council of Censors, who were responsible for amending the constitution, giving its powers to the legislature. The constitution was amended in 1913 to alter election dates to November.

U.S. Representative Luke P. Poland chaired the committee that investigated the Crédit Mobilier scandal. U.S. Senator George F. Edmunds proposed the creation of the Electoral Commission to mediate the results of the 1876 presidential election.

Redfield Proctor, the founder of the Vermont Marble Company, established his family's control over Vermont politics. Four members of the Proctor family served as governor (Redfield, Fletcher D. Proctor, Redfield Proctor Jr., and Mortimer R. Proctor) and members of the family's company were active in state politics. Allen M. Fletcher, a relative of the Proctor family, also served as governor. The Proctor family's power ended with the defeat of Mortimer by Ernest W. Gibson Jr. in the 1946 Republican gubernatorial primary. The family later sold their company to a Swiss organization.

A primary system was created by the legislature in 1915, ending the previous method of selecting candidates through convention votes. Percival W. Clement unsuccessfully ran for governor in 1902 and 1906 Vermont gubernatorial election under the convention system, but won the Republican primary and general election in 1918.

Edna Beard became the first woman to serve in the legislature with her election in 1920. John E. Weeks was the first governor to win reelection following the 1870 amendments to the constitution with his victory in the 1928 election.

The State Board of Health was organized in 1886. A gasoline tax was introduced in 1923, and an income tax was passed in 1931, to pay for the creation of a state highway system. The Vermont State Guard was created in 1941.

Modern The population of Vermont grew slowly during the first half of the 20th century, but grew rapidly in the 1960s and 1970s. The 1970 census reported that one-fourth of the state's population was born outside of it. The U.S. Supreme Court case Reynolds v. Sims forced Vermont to alter its districting in 1965, which benefitted the Democrats.

William H. Meyer's election to the U.S. House of Representatives in the 1958 election was the first time that a Democrat won a statewide election in Vermont since 1853. Democratic nominee Philip H. Hoff won the 1962 gubernatorial election, the first defeat for the Republican in the gubernatorial race, with the support of the Independent Party, an organization formed by dissident Republicans. Lyndon B. Johnson's victory in the 1964 election made him the first Democrat to win the state in a presidential election. The Democrats also won the positions of lieutenant governor, secretary of state, attorney general, treasurer, and auditor in 1964. Timothy J. O'Connor was selected as Speaker of the House in 1975, and the Democrats gained a majority in the state house in 1976, and state senate in 1984.

Hoff was the first Democratic governor to endorse an opponent to Johnson, Robert F. Kennedy, during the 1968 Democratic presidential primaries. A primary system was instituted for the presidential selection in 1976.

A 3% sales tax was introduced under Governor Deane C. Davis in 1969 to pay for welfare programs.

Consuelo N. Bailey's election in 1954 made her the first woman to serve in as lieutenant governor in the United States. Madeleine Kunin's victory in the 1984 election made her Vermont's first female governor.

The 1986 gubernatorial election was the first time since 1912 that none of the candidates received a majority of the vote.

Bernie Sanders' election to the U.S. House of Representatives in the 1990 election made him the first independent elected to statewide office in Vermont.

In 1985, the Vermont legislature passed and in 1986 voters narrowly defeated an equal rights amendment to the Vermont constitution. However, in 2007 Governor Jim Douglas signed a landmark civil rights bill banning discrimination on the basis of gender identity by employers, financial institutions, housing, public accommodations, and other contexts, after it had passed both chambers of the legislature by a veto-proof majority.Acts and Resolves of the 2007–2008 session of the Vermont General Assembly, Act 41 (S.51). leg.state.vt.us Douglas previously had vetoed a similar bill in 2006.H.865 from the 2005–2006 legislative session. leg.state.vt.us .