Although at times the 1787 Constitutional Convention became bogged down in details, the delegates generally debated the “big picture” of crafting a new fundamental document for the United States. Given that bias for the larger topics, it is not surprising the delegates did not discuss at any length the age requirement for serving as a member of the House of Representatives, in the Senate, or as the President. What concerned them was not the age of the individual, but the quality of the representation provided to the people by those individual federal representatives.

During the convention, on May 29, 1787, Edmund Randolph of Virginia proposed what is now known as the Virginia Plan, originally drafted by James Madison. The fourth resolution stated: “that the members of the branch of the national Legislature ought to be elected by the people of the several States every           for the term of           ; to be the age of           years at least . . .” Randolph and Madison left the specifics of elections and the ages of the members of the legislatures open for the convention to debate. Several weeks later, on June 22, the conversation in the convention turned to the issue of the election, length of service, and age of eligibility for members of the House. George Mason of Virginia rose and proposed 25 years of age as a qualification for the members of the first branch (House of Representatives). Mason’s motion passed seven states in favor, three opposed, and New York divided. Three days later, the convention took up Randolph’s resolution again, this time addressing the second branch (the Senate), and unanimously agreed to the clause requiring the age of members to be at least 30 years of age.

Since what most concerned the members of the convention were what Mason called “the danger of the majority oppressing the minority, and the mischievous influence of demagogues,” details such as the specific ages required to become representatives and senators did not rise to the level of major debate. Other issues were deemed far more important, such as how to elect the executive and the specific powers of the president, because of the controversial and dangerous nature of the proposed executive. The age requirements for president were included in the final recommendations that were agreed to by the Committee of Eleven (one member from every state). These required that the president be a “natural born citizen” at the time of the Constitution’s adoption, must have lived in the United States at least 14 years, and be no less than 35 years old.

Further evidence that the supporters of the proposed 1787 Constitution considered the issue of ages a detail can be found in the Federalist Papers. What concerned Publius (the pseudonym used by Alexander Hamilton, James Madison, and John Jay) was not the age of the representatives (mentioned only in passing in Federalist 51-54), but the timing and frequency of elections to maintain accountability to the people in the states. Biennial elections allowed representatives to reflect the changing moods of the electorate at home while providing institutional stability in the House.

The Federalist Papers also address requirements for office. In Federalist 62, Publius examines the constitutional requirement for becoming a senator. Again, it was not the age of the individual that mattered so much as the length of residency in the country and the individual’s level of maturity. The differing requirements for Senate (vs. House of Representatives), Publius wrote, “is explained by the nature of their 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.” So too with the proposed presidency; Publius argues in Federalist 67-71 that the older age was needed because of the burden, trust, and perspectives needed in an executive.

Thus, while it would be wrong to say that the members of the Federal Convention assigned the ages haphazardly, it would also be wrong to say that they spent much time debating the virtues of 25, 30, and 35 years old to hold federal elected office. Rather, they followed the patterns already established in the states, and they increased the ages as the importance and burdens of federal office increased.

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.

After the War of 1812, the northern, free states' members in the House of Representatives exceeded those from slave states. The slave states reckoned then that Congress could try to outlaw slavery in the South. Their representatives in the House had tried to stave off attempts by that chamber to legislate the abolition of slavery by instituting a "gag rule" which, for years, had blocked abolitionist petitions from reaching the floor of the House, but which had been rescinded in 1844. The South therefore worked out a strategy to ensure that they would not be outnumbered in the Senate. If they maintained a balance in the Senate, they figured, attempts to force the end of slavery on the southern states could be blocked.

To maintain this balance as new territories were admitted into the Union, slave states and free states were admitted, roughly speaking, in pairs: Mississippi and Indiana, Alabama and Illinois, Missouri and Maine, Arkansas and Michigan, and Florida and Iowa. In some cases, the admission of a state was slowed or sped up in order to pair it with another. This practice was the outcome of a strategy that the South considered essentially defensive. The South's primary aim in this was not so much to spread slavery as it was to protect slavery where it already existed. To do that, it had to protect its strength in the Senate, and for that to happen as northern territories were brought into the Union, the South had to find southern territories to balance them. Eventually, this even led some in the South to look for possible ways to annex Cuba and Nicaragua and bring them into the Union as slave states.

Texas and Wisconsin were considered to be a pair. Partly due to objections of northern abolitionists who feared that the admission of Texas by itself would tilt the Senate balance in favor of the South, the Lone Star State's entrance into the Union was delayed until December 29, 1845, and only happened then because of the successful Democratic campaign of 1844 that succeeded in electing James Polk to the White House on a platform that combined a call for admitting Texas into the Union with an expansionist stance on the question of setting the northern territorial claims of Oregon as far as possible. The northern vote was split in that election, between Whig candidate Henry Clay, Liberty Party candidate James Birney, and James Polk (partly because of his party's position on Oregon), giving the election to Polk.

There was a strong effort to bring Wisconsin into the Union in 1846, along with Iowa, but Wisconsin was not admitted until May 29, 1848. Did that make the Senate balanced in the South's favor between the time of the admission of Texas and the admission of Wisconsin? Not really. For one thing, the balance in fact was volatile.

For example, although Iowa had been admitted to the Union as a free state on December 28, 1846, political turmoil in its state legislature, almost evenly divided on party lines, and spiced by accusations of bribery, resulted in the state's inability at first to elect U.S. Senators to send to Congress. In addition, party politics factored into votes, with northern Democrats, for example, sometimes voting with their southern colleagues. Nevertheless, a rough parity existed in the Senate, although the South recognized it as tenuous.

South Carolina Senator John C. Calhoun's speech in the Senate on February 19, 1847, described the situation in which the South perceived itself at the time:

Sir, already we are in a minority—I use the word 'we' for brevity sake—already we are in a minority in the other House, in the electoral college, and, I may say, in every department of this government, except at present, in the Senate of the United States—there, for the present, we have an equality. Of the twenty-eight States, fourteen are non-slaveholding and fourteen are slaveholding, counting Delaware, which is doubtful, as one of the non-slaveholding States. But this equality of strength exists only in the Senate. … We, Mr. President, have at present, only one position in the government, by which we may make any resistance to this aggressive policy which has been declared against the South; or any other, that the non-slaveholding States may choose to take. And this equality in this body is of the most transient character. Already, Iowa is a State; but, owing to some domestic calamity, is not yet represented in this body. When she appears here, there will be an addition of two Senators to the Representatives here, of the non-slaveholding States. Already, Wisconsin has passed the initiatory stage, and will be here at next session. This will add two more, making a clear majority of four in this body on the side of the non-slaveholding States, who will thus be enable to sway every branch of this government at their will and pleasure. But, sir, if this aggressive policy be followed—if the determination of the non-slaveholding States is to be adhered to hereafter, and we are to be entirely excluded from the territories which we already possess, or may possess—if this is to be the fixed policy of the government, I ask what will be our situation hereafter?

Calhoun was reacting here to the introduction of the "Wilmot Proviso," an attempt by northern anti-slavery congressmen to ban slavery in all territories that would enter U.S. possession in the future. Far from seeing itself at this point as capable of taking advantage of its senatorial strength, the South—as is clear from Calhoun's speech—saw itself as barely able to hold its defenses against an aggressive North intent on outlawing slavery everywhere. In his speech, Calhoun calculated that if all the territories were thenceforth brought into the Union as free states, the slave states would be outnumbered in the Senate by two to one.

The Wilmot Proviso was defeated in the Senate—that was as close as one could say that the South was able to "take advantage of" its strength there—but the battle over it served to turn opposing political forces further into sectional differences, North versus South, free state versus slave state. By doing this, it also helped to redefine the politics of the time away from party affiliation and loyalty to sectional affiliation. Both the Whigs and the Democrats underwent fragmentation and inner realignments during this period.

When California was admitted on September 9, 1850, its formal admission came only five days after the passage of the bills that formed the Compromise of 1850. As part of the Compromise, California came in as a single free state, rather than divided into two parts, one free and one slave, but Utah and New Mexico territories were organized to allow popular votes in the territories to decide later whether slavery would be permitted. In point of fact, the admission of California did not immediately change the balance of anti- vs. pro-slavery votes in the Senate because California, although a free state, sent one anti-slavery senator and one pro-slavery senator to Washington.