Article V of the Constitution says how the Constitution can be amended—that is, how provisions can be added to the text of the Constitution. The Constitution is not easy to amend: only twenty-seven amendments have been added to the Constitution since it was adopted.
Article V spells out a few different ways in which the Constitution can be amended. One method—the one used for every amendment so far—is that Congress proposes an amendment to the states; the states must then decide whether to ratify the amendment. But in order for Congress to propose an amendment, two-thirds of each House of Congress must vote for it. And then three-quarters of the states must ratify the amendment before it is added to the Constitution. So if slightly more than one-third of the House of Representatives, or slightly more than one-third of the Senate, or thirteen out of the fifty states object to a proposal, it will not become an amendment by this route. In that way, a small minority of the country has the ability to prevent an amendment from being added to the Constitution.
Article V does potentially provide a way for the states to bypass Congress, although it has never been used. Article V says that “on the Application of two thirds of the Legislatures of the several States, [Congress] shall call a Convention for proposing amendments.” The convention can propose amendments, whether Congress approves of them or not. Those proposed amendments would then be sent to the states for ratification. As with an amendment proposed by Congress, three-quarters of the states would have to ratify the amendment for it to become part of the Constitution.
Article V also allows Congress to choose between two ways that the states might ratify an amendment. An amendment can be ratified by the state legislature—the part of the state government that enacts laws for the state. But Congress can provide instead that the states must call conventions for the single purpose of deciding whether to ratify an amendment. So far, though, with one exception (the Twenty-First Amendment), every amendment has been ratified by state legislatures.
The amendments to the Constitution have come in waves. The first twelve Amendments, including the Bill of Rights, were added by 1804. Then there were no amendments for more than half a century. In the wake of the Civil War, three important Amendments were added: the Thirteenth (outlawing slavery) in 1865, the Fourteenth (mainly protecting equal civil rights) in 1868, and the Fifteenth (forbidding racial discrimination in voting) in 1870. At the time, there were questions about whether those Amendments had been properly ratified by the states, because it was unclear whether the Confederate states—which had seceded from the Union—were part of the United States again. Today, though, no one doubts that those Amendments are part of the Constitution.
After the Civil War Amendments, another forty-three years passed until the Constitution was amended again; then four more Amendments (Sixteen through Nineteen) were added between 1913 and 1920. Seven more amendments were adopted at pretty regular intervals between 1920 and 1971, but except for one very unusual amendment, there have been no amendments to the Constitution since 1971.
The unusual amendment is the Twenty-Seventh Amendment. It was proposed with the original Bill of Rights, in 1789, and was ratified by a half-dozen states within a few years—and then mostly ignored. But Article V says nothing about the time period within which three-quarters of the states have to ratify a proposed amendment. From time to time, another state would add its ratification. Finally, in 1992, more than two hundred years after the Amendment was first proposed, the ratifications finally reached the three-quarters line, and the Twenty-Seventh Amendment has been considered part of the Constitution since then. For recent proposed amendments, though, Congress has specified that the amendment must be ratified within seven years or it would lapse, so this situation is unlikely to happen again.
But other issues might arise. For example, Article V says that an amendment that has been proposed to the states will become part of the Constitution if three-quarters of the states ratify it. What if a state ratifies quickly, but then, before many other states ratify, changes its mind and tries to rescind (that is, take back) its ratification—can a state do that? Some commentators would say no—once a state has ratified, that counts toward the required three-quarters, no matter what the state does later. But other commentators would say that a state can rescind its ratification so long as it does so before the amendment process has been completed. Thus, there is no definite answer to this question. This kind of uncertainty might be very troubling—we might not know for sure whether a proposed amendment was part of the Constitution or not.
Finally, Article V, while spelling out how the Constitution can be changed, made two things unchangeable—even through the difficult amendment process. One is that “no State, without its consent, shall be deprived of its equal Suffrage in the Senate.” So every state will have the same number of Senators, no matter how many members of Congress or other states want to change that part of our system (unless a state agrees to accept a smaller number of Senators). Article V also says, in language that is hard to follow and has no legal effect today, that until 1808, no amendment could limit the slave trade—a reminder that there are parts of the Constitution that we can be thankful were amended.