Democrats will control the Senate majority for the first time in six years, ensuring that they will run the 20 permanent committees, seeking to carry out President Biden’s agenda and handling the confirmation of nominees for the administration and the federal judiciary. The advantage is razor-thin with 50 Democrats, 50 Republicans and Vice President Harris the tie-breaking vote.

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A look at the likely committee chairs:

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Agriculture

Sen. Debbie Stabenow (Mich.) — Stabenow, 70, the senior senator from Michigan and member of the Senate leadership, served as chair of the committee from 2011 to 2015. She was most recently the ranking Democrat on the committee, which is responsible for agriculture policy, school nutrition and the nation’s Supplemental Nutrition Assistance Program.

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Appropriations

Sen. Patrick J. Leahy (Vt.) — Leahy, 80, the longest-serving active senator, has been a member of the committee for more than four decades and was most recently its top Democrat. The committee is responsible for legislation that allocates federal funding to government agencies, departments and organizations. He again became the Senate’s president pro tempore.

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Armed Services

Sen. Jack Reed (R.I.) — Reed has most recently been the ranking Democrat on the committee, previously opposite Sen. John McCain (R-Ariz.) and then Sen. James M. Inhofe (R-Okla.). Reed was a graduate of the Army Ranger course and is an alumnus of the U.S. Military Academy and Harvard University. The committee has legislative jurisdiction over the nation’s military and defense.

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Banking, Housing and Urban Affairs

Sen. Sherrod Brown (Ohio) — Brown, an outspoken Wall Street critic, was part of the opposition to legislation rolling back some Dodd-Frank regulations, the massive reform package to prevent another financial crisis like the one in 2008. He was most recently the top Democrat on the committee, which is responsible for legislation related to banking and financial institutions, as well as government contracts and urban mass transit.

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Budget

Sen. Bernie Sanders (Vt.) — Sanders,an independent Senator who caucuses with the Democrats, has had a prominent perch as the ranking member on the committee, which is responsible for drafting federal budget plans, a key post for challenging Republican funding priorities. He took over the ranking member post in 2015. The 79-year-old two-time runner-up for the Democratic presidential nomination is a self-proclaimed democratic socialist.

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Commerce, Science and Transportation

Sen. Maria Cantwell (Wash.) — The four-term senator who previously worked in the tech industry became the top Democrat on the committee in 2019, after serving as the ranking Democrat on the Senate Energy and Natural Resources Committee. The committee has legislative jurisdiction over interstate commerce, transportation, and research and development of science, engineering and technology.

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Energy and Natural Resources

Sen. Joe Manchin III (W.Va.) — Manchin, who arrived in the Senate in 2010, faced criticism over his environmental record in 2018 when he was tapped for the top Democratic spot on the committee. The coal-friendly Democrat, who represents the state with the second-highest coal production in the nation, had embraced some of the Trump administration’s environmental initiatives. In an infamous 2010 campaign ad, he fired a shot at a cap-and-trade bill. He was most recently the ranking Democrat on the committee, which has jurisdiction over matters related to energy resources and development as well as public lands.

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Environment and Public Works

Sen. Thomas R. Carper (Del.) — Carper helped lead his Senate colleagues in questioning President Donald Trump’s Environmental Protection Agency nominees as the ranking Democrat on the committee. The senior senator from Delaware and former governor of the state is a co-founder of the Senate Environmental Justice Caucus. The committee is responsible for issues related to environmental policy and water resources, as well as fisheries and wildlife.

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Finance

Sen. Ron Wyden (Ore.) — Wyden, who has previously chaired the committee that handles matters related to taxation and revenue, is expected to take the gavel again. He was most recently the commitee’s ranking Democrat. There is broad overlap between Wyden and Biden’s tax proposals, and the senior senator from Oregon, who won his fourth full-term in 2016, has said the pair are on the “same page on taxes.”

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Foreign Relations

Sen. Robert Menendez (N.J.) — Menendez is set to retake the committee gavel after leading the panel from 2013 to 2015. He resumed his position as ranking member of the committee in 2018 after federal prosecutors asked a judge to dismiss corruption charges against the Democrat from New Jersey. Menendez was reelected to a third term in 2018. The committee, which evaluates nominees to the State Department, holds jurisdiction over all diplomatic nominations.

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Health, Education, Labor and Pensions

Sen. Patty Murray (Wash.) — Murray is expected to take the helm of the chamber’s key health-care committee after another election cycle in which health care was a key issue for voters who were grappling with an ongoing pandemic. She has been a member of the committee for more than two decades and most recently was the ranking Democrat on the panel. Murray, 70, has been a member of Senate Democratic leadership since 2007.

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Homeland Security and Governmental Affairs

Sen. Gary Peters (Mich.) — Peters won reelection to his second Senate term. He most recently served as the ranking Democrat on the Senate’s primary oversight committee, which oversees the federal workforce and the U.S. Postal Service, and also has broad national security responsibilities.

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Indian Affairs

Sen. Brian Schatz (Hawaii) — Schatz was most recently the fourth-ranking Democrat on the committee and could take the helm after the ranking Democrat, Sen. Tom Udall (N.M.), retired and as the next two senators on the Democratic seniority list, Cantwell and Jon Tester (Mont.), are set to lead other panels. Schatz is the senior senator from Hawaii, a seat he has held since 2012. The committee’s jurisdiction includes matters related to American Indian, Native Hawaiian and Alaska Native people.

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Judiciary

Sen. Richard J. Durbin (Ill.) is next in line to lead the committee after Sen. Dianne Feinstein (Calif.) announced in November that she would not seek the top Democratic spot on the panel following criticism of her handling of Supreme Court Justice Amy Coney Barrett’s confirmation hearings. Durbin, who is also the Senate Democratic whip, has served for more than two decades on the Judiciary Committee, which is tasked with consideration of judicial nominations, including nominations to the Supreme Court, and is also responsible for oversight of the Justice Department and its agencies.

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Rules and Administration

Sen. Amy Klobuchar (Minn.) — Klobuchar is set to take the gavel of the committee that oversees the rules and operations of the Senate. The senior senator from Minnesota ran for the Democratic presidential nomination in 2020 and has served as the ranking Democrat on the committee since 2017. Klobuchar is also the chair of the Senate Democratic Steering and Outreach Committee. She recently said on CNN that the role will “give me the ability to work on issues related to elections where I was blocked before, antitrust, things that I really care a lot about.”

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Ethics

Sen. Christopher A. Coons (Del.) — Coons, who was reelected to his second full Senate term in November, joined the ethics panel in 2015 and became its top Democrat in 2017. The panel is tasked with investigating alleged violations of Senate rules. The Democrat from Delaware was elected to his first full term in the Senate in 2014 after first being elected in a 2010 special election.

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Intelligence

Sen. Mark R. Warner (Va.) — Warner won reelection to a third term in the Senate in November and would take the helm of a committee on which he has been the top Democrat since 2017. The panel, which oversees matters related to the nation’s intelligence community, has been at the center of several high-profile issues, including the investigation into Russian interference in the 2016 election. Warner previously served as governor of Virginia.

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Small Business and Entrepreneurship

Sen. Ben Cardin (Md.) — Before being elected to the Senate in 2006, Cardin represented Maryland’s 3rd Congressional District from 1987 to 2006 and served for 17 years on the House Ways and Means Committee. He was most recently the ranking Democrat on the Senate Small Business Committee, which has jurisdiction over the Small Business Administration.

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Special Committee on Aging

Sen. Robert P. Casey Jr. (Pa.) — Casey most recently served as the top Democrat on the committee, which oversees health-care access for America’s seniors. He is also a member of the Senate Finance Committee; the Senate Agriculture, Nutrition, and Forestry Committee; and the Senate Health, Education, Labor and Pensions Committee. He was reelected to a third term in 2018.

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Veterans’ Affairs

Sen. Jon Tester (Mont.) — The senior senator from Montana, where veterans make up about 10 percent of the population, has been the top Democrat on the committee since 2017. He drew Trump’s ire in 2018 after he released damaging information about former White House physician Ronny L. Jackson, ending Jackson’s prospects of leading the Department of Veterans Affairs. The panel is responsible for oversight of Veterans Affairs as well as measures related to veterans’ hospitals and medical care.

Correction: A previous version of this article incorrectly stated Sen. Jack Reed’s military credentials. Reed qualified as an Army Ranger.