The Senate has exclusive power to confirm U.S. presidential appointments to high offices, and (by two-thirds supermajority to pass main motions) approve or reject treaties, and try cases of impeachment brought by the House.

The Senate has typically been considered both a more deliberative[5] and prestigious[6][7][8] body than the House of Representatives due to its longer terms, smaller size, and statewide constituencies, which historically led to a more collegial and less partisan atmosphere.

In the end, some small states—unwilling to give up their equal power with larger states under the Articles of Confederation—threatened to secede[11] in 1787, and won the day by a vote of 5–4 in what became known as the Connecticut Compromise.

The Constitution provides several unique functions for the Senate that form its ability to "checks and balances" the powers of other elements of the federal government.

The upper house may add to them what it pleases; may go altogether outside of their original provisions and tack to them entirely new features of legislation, altering not only the amounts but even the objects of expenditure, and making out of the materials sent them by the popular chamber measures of an almost totally new character.

Both Houses must pass the same version of the bill; if there are differences, they may be resolved by sending amendments back and forth or by a conference committee, which includes members of both bodies.

The majority of nominees are confirmed; however, in a small number of cases each year, Senate committees purposely fail to act on a nomination to block it.

Furthermore, as the Supreme Court held in Myers v. United States, although the Senate's advice and consent are required for the appointment of certain executive branch officials, it is not necessary for their removal.

Under the Twelfth Amendment, the Senate has the power to elect the vice president if no vice-presidential candidate receives a majority of votes in the Electoral College.

62, James Madison justified this arrangement by arguing that the "senatorial trust" called for a "greater extent of information and stability of character": A senator must be thirty years of age at least; as a representative must be twenty-five.

The propriety of these distinctions is explained by the nature of the senatorial trust, which, requiring greater extent of information and stability of character, requires at the same time that the senator should have reached a period of life most likely to supply these advantages; and which, participating immediately in transactions with foreign nations, ought to be exercised by none who are not thoroughly weaned from the prepossessions and habits incident to foreign birth and education.

The term of nine years appears to be a prudent mediocrity between a total exclusion of adopted citizens, whose merits and talents may claim a share in the public confidence, and an indiscriminate and hasty admission of them, which might create a channel for foreign influence on the national councils.

In Louisiana, the blanket primary is considered the general election and candidates receiving a majority of the votes is declared the winner, skipping a run-off.

The Seventeenth Amendment permits state legislatures to empower their governors to make temporary appointments until the required special election takes place.

[41]: 9 [43] In September 2009, Massachusetts changed its law to enable the governor to appoint a temporary replacement for the late senator Edward Kennedy until the special election in January 2010.

[46] As a result, it is uncertain whether an Alaska governor may appoint an interim senator to serve until a special election is held to fill the vacancy.

[48] Congress has prescribed the following oath for all federal officials (except the President), including senators: I, ___ ___, do solemnly swear (or affirm) that I will support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I take this obligation freely, without any mental reservation or purpose of evasion; and that I will well and faithfully discharge the duties of the office on which I am about to enter.

[53] Along with earning salaries, senators receive retirement and health benefits that are identical to other federal employees, and are fully vested after five years of service.

When senators have been in office for the same length of time, a number of tiebreakers are used, including comparing their former government service and then their respective state population.

Instead, they have usually presided only on ceremonial occasions, such as swearing in new senators, joint sessions, or at times to announce the result of significant legislation or nomination, or when a tie vote on an important issue is anticipated.

If the Senate invokes cloture, the debate does not necessarily end immediately; instead, it is limited to up to 30 additional hours unless increased by another three-fifths vote.

The longest filibuster speech in the Senate's history was delivered by Strom Thurmond (D-SC), who spoke for over 24 hours in an unsuccessful attempt to block the passage of the Civil Rights Act of 1957.

Supporters generally consider the filibuster to be an important protection for the minority views and a check against the unfettered single-party rule when the same party holds the Presidency and a majority in both the House and Senate.

Closed sessions are rare and usually held only when the Senate is discussing sensitive subject matter such as information critical to national security, private communications from the president, or deliberations during impeachment trials.

[80][81] One analysis of democracies by Harvard professors Daniel Ziblatt and Steven Levitsky found that only Argentina and Brazil's upper chambers deviate further from the one person, one vote principle than the U.S. Senate does.

[82] This disparity in representation between large and small states has increasingly favored Republicans since the 1960s,[83][84][85] with David Wasserman estimating in 2018 that Democrats would need to keep winning the popular vote by more than 6% to maintain control of the Senate.

He also documents 21st century examples of how this malaportionment has led to the party receiving the most votes losing control of the Senate (and as a result, the Judiciary) and predicts the trend looks set to continue and possibly increase.

James Madison emphasized that the Senate serves as a check against the potential tyranny of the majority, ensuring that the interests of smaller states are not drowned out by the more populous ones.

[91] Yale legal scholar Akhil Reed Amar, in his book "America's Constitution: A Biography," explains that the Senate's structure is integral to the federal system, ensuring that smaller states have a voice in the democratic process.

Equal representation for smaller states was pivotal for the legislative accomplishments of the Clinton presidency, like the Omnibus Budget Reconciliation Act of 1993, and the Obama presidency, like the Affordable Care Act, at a time when Democrats earned more seats in lower population states like North Dakota, South Dakota, Montana, West Virginia, Nebraska, and Iowa.