MO - Missouri

Congress established the Territory of Missouri and granted its residents the right to vote for a legislature.

The Senate debated the slavery question in new territories and future states and finally agreed to the Missouri Compromise, which admitted Maine as a free state and allowed the Territory of Missouri to draft a constitution and form a state government without restrictions on slavery. The compromise established that states to the south of 36º30’ could permit slavery, while states to the north of that line would prohibit slavery.

Missouri became the 24th state in the Union.

David Barton of St. Louis took his oath of office as one of Missouri's first two United States senators. Three days later, on December 6, Thomas Hart Benton of St. Louis presented his credentials and was sworn into office. The two senators then drew lots to determine their class assignments. Barton drew Class 2, with a term to expire on March 3, 1825. Benton drew Class 3, with a term to expire March 3, 1827.

Thomas Hart Benton became chairman of the Senate Committee on Indian Affairs, serving until 1828. He then became chairman of the Senate Committee on Military Affairs (today's Committee on Armed Services), a position he held until 1841 and again from 1845 to 1849.

Lewis F. Linn of Saint Genevieve became chairman of the Senate Committee on Agriculture (today's Committee on Agriculture, Nutrition, and Forestry), serving until 1843.

David Rice Atchison of Gower was elected president pro tempore of the Senate. Over the next 8 years, Senator Atchison would serve in that leadership position 13 different times.

David Rice Atchison became chairman of the Senate Committee on Indian Affairs serving until 1853.

Senator David Rice Atchison maintained a dubious claim to have assumed the office of president of the United States one day. As the Senate's president pro tempore, he was then second in line of presidential succession behind the vice president. The terms of President James K. Polk and Vice President George M. Dallas expired at noon on March 4, a Sunday, and President-elect Zachary Taylor was not inaugurated until Monday, March 5. Atchison boasted for the rest of his life that he technically became president during that short interim, despite the expiration of his own senate term on March 4.

Senator Thomas Hart Benton briefly became chairman of the Senate Committee on Foreign Relations, serving during the special session until March 23, 1849.

During heated debate on the Senate floor, Mississippi senator Henry Foote pulled a pistol on Senator Thomas Hart Benton as the physically imposing Benton moved toward him down the center aisle. Foote claimed self-defense, while Hart accused Foote of being an assassin. As tempers cooled, a committee was immediately appointed to look into the disorder and the matter quietly went away.

Senator Thomas Hart Benton took to the Senate floor to give a classic speech in opposition to the Compromise of 1850, which dealt primarily with the issues of slavery and western expansion. Not particularly known as an orator, Benton was nevertheless a major figure in the Senate where he had served for nearly 30 years.

Thomas Hart Benton completed his service in the Senate after a record 29 years, 6 months, and 22 days. Senator Benton's service record would stand for over 40 years until it was surpassed by Ohio's John Sherman in 1894. By 2009, Senator Robert C. Byrd of West Virginia had pushed the record for longest serving senator over the 50-year mark. Benton remains Missouri's second longest-serving senator behind Francis Cockrell of Warrensburg.

Both Missouri senators, Waldo P. Johnson of Osceola and Trusten Polk of St. Louis, were expelled from the Senate for disloyalty to the Union.

Senator John B. Henderson of Lincoln County became chairman of the Senate Committee on Indian Affairs serving until 1853.

Future senator Francis P. Blair of St. Louis was the unsuccessful Democratic vice presidential candidate in the 1868 election. Blair was the running mate of former New York governor Horatio Seymour. They lost the election to the Republican ticket of Ulysses S. Grant and Schuyler Colfax.

Charles D. Drake of St. Louis became chairman of the Senate Committee on Education, (today's Committee on Health, Education, Labor, and Pensions), serving until 1870.

Future senator George Vest of Kansas City, then a lawyer in rural Missouri, gained immortality with a speech delivered to a jury in Warrensburg. Prosecuting the case of a farmer whose dog had been killed by a neighbor, Vest eulogized the dog as "man's best friend." Vest was elected to the Senate nine years later and served there for 24 years (1879–1903).

Former senator Benjamin Gratz Brown of St. Louis was the unsuccessful Democratic vice presidential candidate in the 1872 election. Brown was the running mate of newspaperman Horace Greeley. They lost the election to the Republican ticket of the incumbent Ulysses S. Grant and Massachusetts senator Henry Wilson.

The Senate resolved the disputed election case of Lewis V. Bogy of St. Louis. Thirteen days after Senator Bogy had initially taken his seat the Senate began an investigation into allegations that Bogy had won his seat through bribery and corruption. The Senate's Committee on Privileges and Elections quickly determined there was a lack of evidence and concluded the matter. Bogy continued to serve in the Senate until his death in 1877.

By a vote of 55 to 1, the Senate confirmed the nomination of former senator Carl Schurz as secretary of the interior under President Rutherford B. Hayes. Schurz served as interior secretary until 1881.

James Shields of Carrollton won election to Missouri's Class 3 Senate seat. Shields had previously represented both Illinois and Minnesota in the Senate. He is the only Senator to ever have served from three different states.

Francis M. Cockrell became chairman of the Senate Committee on Appropriations, serving until 1895.

A marble statue of former senator Francis P. Blair and a marble statue of former senator Thomas Hart Benton, both by sculptor Alexander Doyle, were accepted by the Senate as Missouri's contributions to the National Statuary Hall Collection.

Francis M. Cockrell ended his Senate service as Missouri's longest-serving senator. Cockrell served for exactly 30 years, about six months longer than his fellow Missourian Thomas Hart Benton.

William J. Stone of Jefferson City became chairman of the Senate Committee on Indian Affairs, serving until 1914, when he became chairman of the Senate Committee on Foreign Relations. He led that committee until 1918.

Incumbent senator William J. Stone became Missouri's first directly elected senator following the passage of the Seventeenth Amendment in 1913.

Selden P. Spencer of St. Louis became chairman of the Senate Committee on Indian Affairs serving until 1923.

Senator James Reed of Kansas City read George Washington's Farewell Address on the floor of the Senate, a tradition dating to 1862.

Senator Harry S. Truman, who had entered the Senate in 1935, was appointed chairman of the Special Committee to Investigate the National Defense Program, which was created to uncover defense-related waste and corruption during the mobilization prior to World War II. The committee became popularly known as the "Truman Committee" and helped propel Senator Truman to national prominence, the office of vice president, and ultimately, the presidency itself.

Senator Harry S. Truman became the Democratic vice presidential nominee for the 1944 election. Truman was the running mate of incumbent president Franklin D. Roosevelt. They won the general election on November 7, defeating the Republican ticket of New York governor Thomas E. Dewey and future Ohio senator John W. Bricker.

Vice President Harry S. Truman became the 12th senator to become president of the United States following the death of President Franklin D. Roosevelt.

A marble bust of Vice President Harry S. Truman by artist Charles Keck was added to the Senate Vice Presidential Bust Collection. Truman served as a senator from Missouri from 1935 to 1945 and as vice president in 1945. The bust was commissioned in 1946 and was modeled for by Truman in the White House while he was president.

Senator Thomas C. Hennings of St. Louis was elected the Democratic Conference secretary. He served in that leadership position until 1960.

Thomas C. Hennings became chairman of the Senate Committee on Rules and Administration, serving until 1960.

The Senate confirmed the nomination of Missourian Charles E. Whittaker as an associate justice of the Supreme Court.

Among former senator and president Harry S. Truman's recommendations to the Senate's Special Committee on the Senate Reception Room, which was seeking to identify five outstanding former senators whose portraits would be permanently displayed in that room, were Missouri senators Thomas Hart Benton and George Vest. Although they weren't included among the "famous five," the Senate committee recommended that Benton be considered for future honors.

Former senator and president Harry S. Truman returned to the Senate and was honored on the occasion of his 80th birthday. The Senate had recently modified its rules to allow former presidents to address the body, a rule change once advocated by Truman during his time in the Senate.

Senator Thomas F. Eagleton of St. Louis became the Democratic vice presidential nominee for the 1972 election. A month later, however, presidential nominee and South Dakota senator George McGovern replaced Eagleton on the ticket with Sargent Shriver due to health concerns.

John C. Danforth of St. Louis became chairman of the Senate Committee on Commerce, Science, and Transportation, serving until 1987.

Senator Christopher "Kit" Bond of St. Louis became chairman of the Senate Committee on Small Business and Entrepreneurship, serving until 2001.

Senator John D. Ashcroft of Springfield received the Golden Gavel Award for presiding over the Senate for 100 hours in a single session.

Jean Carnahan was appointed to the Senate to fill the vacancy caused by the death of her husband, Governor Mel Carnahan, who was posthumously elected a month after he was killed in a plane crash while campaigning. Senator Carnahan, Missouri's first woman senator, served until November 25, 2002, when an elected successor, James M. Talent of St. Louis, took office for the remainder of the term.

By a vote of 58 to 42, the Senate confirmed the nomination of former senator John D. Ashcroft as attorney general of the United States under President George W. Bush. Ashcroft served as attorney general until 2005.

Senator Jean Carnahan received the Golden Gavel Award for presiding over the Senate for 100 hours in a single session.

Senator Claire McCaskill of Rolla, the second woman to represent Missouri in the Senate, received her first Golden Gavel Award for presiding over the Senate for 100 hours in a single session. She received a second Golden Gavel on September 26, 2008.

Senator Roy Blunt of Strafford, who entered the Senate in 2011 after serving 14 years in the House of Representatives, became Republican Conference vice-chair (formerly the conference secretary), a position he held until 2019 when he became chairman of the Republican Policy Committee.

Roy Blunt became chairman of the Senate Committee on Rules and Administration, a position he held until 2017. He again chaired the committee beginning on April 10, 2018, until February 3, 2021.

As chairman of the Joint Congressional Committee on Inaugural Ceremonies, Roy Blunt accompanied President-elect Donald J. Trump from the White House to the inaugural ceremonies at the Capitol. Four years later, Senator Blunt again chaired the JCCIC for the 59th Inaugural Ceremonies, when Joe Biden and Kamala Harris were sworn in as president and vice president of the United States.