When the Constitutional Convention sent the proposed Constitution to the states for ratification, Anti-Federalists voiced strong objections to it, especially criticizing the strength it invested in the national government and its lack of explicit protections for the rights of individuals. Politicians in several states were able to secure their states' ratification of the Constitution only with the promise that it would be almost immediately amended.

In 1789, James Madison, then an elected member from Virginia of the First Congress's House of Representatives, proposed 19 amendments meant to answer the objections already raised in the states. The Senate consolidated and trimmed these down to 12, which were approved by Congress and sent out to the states by President Washington in October, 1789.

The states ratified the last 10 of the 12 amendments. They became the first 10 amendments to the Constitution, and are now referred to as the Bill of Rights. Not enough states (10 were needed at the time) ratified the first two of Madison's original 12, however, and they did not become law.

The first of these would have established how members of the House of Representatives would be apportioned to the states. It was drafted to ensure that members of the House would continue to represent small constituencies even as the general population grew, small enough that Representatives would not be too far removed from the concerns of citizens. In addition, keeping the House of Representatives from being too small was thought to protect against its becoming a kind of oligarchy. Congress did send this amendment to the states, but the number of states that ratified it was just short of the number needed. Although the proposed amendment did not become law, Congressional apportionment is nevertheless grounded in the Constitution (Article 1, Section 2, Paragraph 3) and the total number of members of the House of Representatives is set by federal statute (currently at 435).

The second of Madison's 12 amendments forbade Congress from giving itself a pay raise: Congress could vote for a raise but it would only apply from the beginning of the next Congress. This amendment also failed to gather the required number of state ratifications in the years after it was introduced. In 1982, however, Gregory Watson, a university student doing research for a government class, ran across a description of this amendment and realized that it remained "alive" because it had included no language in it about a window of time in which it had to gain the needed number of state ratifications. Watson organized a successful effort to lobby various state legislatures, seeking their ratification of the amendment. As a result, the needed number was eventually reached and this amendment, first proposed in 1789, became the 27th (and most recent) amendment to the U.S. Constitution in 1992.

In George Washington’s Farewell Address (1796), the retiring president warned that the creation of political factions, “sharpened by the spirit of revenge,” would most certainly lead to “formal and permanent despotism.” Despite Washington’s cautionary words, two of his closest advisors, Thomas Jefferson and Alexander Hamilton, helped to form the factions that led to the dual party system under which the U.S. operates today. Other men, most notably James Madison and John Adams, also contributed to the formation of political parties, but Hamilton and Jefferson came to represent the divisions that shaped the early national political landscape.

Although both men had been active in the Revolutionary effort and in the founding of the United States, Jefferson and Hamilton did not work together until Washington appointed Jefferson the first secretary of State and Hamilton the first secretary of the Treasury. From the beginning, the two men harbored opposing visions of the nation’s path. Jefferson believed that America’s success lay in its agrarian tradition. Hamilton’s economic plan hinged on the promotion of manufactures and commerce. While Hamilton distrusted popular will and believed that the federal government should wield considerable power in order steer a successful course, Jefferson placed his trust in the people as governors. Perhaps because of their differences of opinion, Washington made these men his closest advisors.

Hamilton’s economic plan for the nation included establishing a national bank like that in England to maintain public credit; consolidating the states’ debts under the federal government; and enacting protective tariffs and government subsidies to encourage American manufactures. All of these measures strengthened the federal government’s power at the expense of the states. Jefferson and his political allies opposed these reforms. Francophile Jefferson feared that the Bank of the United States represented too much English influence, and he argued that the Constitution did not give Congress the power to establish a bank. He did not believe that promoting manufactures was as important as supporting the already-established agrarian base. Jefferson deemed “those who labour in the earth” the “chosen people of God . . . whose breasts he has made his peculiar deposit for substantial and genuine virtue.” He advised his countrymen to “let our work-shops remain in Europe.”

When George Washington’s administration began, the two camps that formed during the Constitutional ratification debates – those groups known as the Federalists and Anti-Federalists – had not yet solidified into parties. But, disagreements over the nation’s direction were already eroding any hope of political unity. In May of 1792, Jefferson expressed his fear to Washington about Hamilton’s policies, calling Hamilton’s allies in Congress a “corrupt squadron.” He expressed fear that Hamilton wished to move away from the Constitution’s republican structure, toward a monarchy modeled after the English constitution. That same month, Hamilton confided to a friend that “Mr. Madison cooperating with Mr. Jefferson is at the head of a faction decidedly hostile to me and my administration, and . . . dangerous to the union, peace and happiness of the Country.”

By the time Jefferson and John Adams vied for the presidency in 1796, political factions had formed under the labels “Republicans” and “Federalists.” In fact, by 1804 the advent of political parties necessitated a constitutional amendment that changed the electoral process to allow president/vice president tickets on the ballot. The Federalists dominated the national government through the end of the 18th century. Despite President Washington’s efforts at unity, political differences proved to be too deep to promote consensus. The Republican Party emerged as organized opposition to Federalist policies, and despite Jefferson’s assurances in his first inaugural address that Americans were “all republicans” and “all federalists,” faction had solidified into party.

Of the 159 nominations for Supreme Court Justice that presidents have submitted to the Senate for confirmation, the Senate has rejected only 12. The first rejection was George Washington's nomination of John Rutledge to be Chief Justice in 1795; the last, Ronald Reagan’s nominee for Associate Justice, Robert H. Bork, in 1987.

In addition to rejecting nominees, the Senate has failed to approve 24 additional nominees by postponing confirmation, taking no action, or by acting in ways that have encouraged nominees to withdraw from consideration, as with Harriet Miers in 2005.

Nearly 60 percent of rejections have occurred when the president and a majority of senators have been members of opposing political parties. Nearly half of the failed conferrals were nominated in a president’s final year in office. One-third of failed appointments were nominations by presidents who had not been elected to office.

“Senatorial courtesy,” whereby senators will vote against a nominee if the nomination is opposed by one of the nominee’s home state senators, when that senator is a member of the same party as the president, also has been a factor in some rejections.

Political science professor P. S. Ruckman, Jr., has argued that in “critical” instances in which a significant shift in the Court’s makeup has been predicted, nominees have been rejected nearly as many times as confirmed. When nominations have not been considered critical, confirmation has been 12 times more likely.

Following an uneventful first 20 years of Senate confirmations, in which all but one of 19 nominees were approved quickly, the confirmation process went through a turbulent 80 years during which the Senate rejected more than one-fourth of nominees. Law Professor Richard D. Friedman concluded, “. . . the probability of a nomination’s rejection peaked in the years surrounding the Civil War, with a dip during the war itself. The probability of rejection then declined gradually, and by 1910 it was close to zero.”

During Reconstruction, Senate opposition to nominees became “politically reputable,” Friedman surmised, as Justices were understood to be politically motivated in their rulings, and Senators thus believed that they had the right and responsibility to vote to insure political reliability and geographical dispersal. (George Washington had established a long-lasting precedent of attempting to have a geographically balanced Supreme Court.)

From 1894 to 1968, only one nominee was rejected (President Hoover’s nominee, North Carolina Circuit Court of Appeals Judge John J. Parker). Beginning in 1968, confirmation battles began again in earnest, as three nominees were rejected between 1968 and 1970. In 1987, Judge Bork was rejected in a politically charged atmosphere, heightened because the voting behavior of the resigning Justice (Lewis F. Powell), had determined a number of important 5-4 decisions.

A 2008 study argued that at present a nominee’s “ideological compatibility” with that of Senators “now takes precedence” over all other factors with regard to their confirmation.