The Constitution of the United States provides two methods for making amendments. Only one has ever been used. The United States Congress can pass a bill setting out a proposed amendment by a vote of two thirds in each body. Or a constitutional convention can be convened by a vote of two thirds of the state legislatures, which will propose one or more amendments. This has never happened and its unclear exactly how such a constitutional convention would operate.
In either case, the amendments to the U.S. Constitution only become effective after being ratified by 3/4 of the states. Some amendments are quickly ratified. The 27th Amendment, on the other hand, was proposed in 1792 and did not achieve final ratification until 1992. Unlike all proposed amendments since Prohibition, this amendment had no deadline.
Some prominent amendments never are ratified. The Equal Rights Amendment was proposed in 1972 and was ratified by 34 of the necessary 38 states. However, advocates could not get the last four states necessary and the Congressionally-imposed deadline for ratification passed.
The first 10 amendments were soon passed and are known collectively as the Bill of Rights. Another cluster of amendments was passed following the Civil War and sought to enshrine the rights of the newly freed slaves.
The United States Constitution now has 25 functioning amendments. There have been 27 ratified in total, but one of these, the 18th, was Prohibition and another, the 21st, was the repeal of Prohibition.
|1St||1791||Rights to Religion, Speech, Press, Assembly, Petition|
|2nd||1791||Right to Bear Arms|
|3rd||1791||Quartering of Soldiers|
|4th||1791||Search and Seizure|
|5th||1791||Grand Jury, Double Jeopardy, Self-Incrimination, Due Process|
|6th||1791||Rights of Accused in Criminal Prosecutions: Rights to Jury Trial, to Confront Opposing Witnesses and to Counsel|
|8th||1791||Protections against Excessive Bail, Cruel and Unusual Punishment|
|10th||1791||Rights Reserved to States|
|11th||1795||Suits Against a State|
|12th||1804||Election of President and Vice-President|
|13th||1865||Abolition of Slavery and Involuntary Servitude|
|14th||1868||Protects rights against state infringements, defines citizenship, prohibits states from interfering with privileges and immunities, requires due process and equal protection, punishes states for denying vote, and disqualifies Confederate officials and debts|
|16th||1913||Federal Income Tax|
|17th||Popular Election of Senators|
|19th||1920||Women’s Right to Vote|
|20th||1933||Commencement of Presidential Term and Succession|
|21st||1933||Repeal of 18th Amendment (Prohibition)|
|22nd||1951||Two-Term Limitation on President|
|23rd||1961||District of Columbia Presidential Vote|
|24th||1964||Abolition of Poll Tax Requirement in Federal Elections|
|25th||1967||Presidential Vacancy, Disability and Inability|
|26st||1971||Right to Vote at Age 18|