What Is a Constitutional Amendment and How Hard Is It to Pass One?

Key Takeaways

Amending the Constitution requires either two-thirds of both houses of Congress AND three-fourths of states (38 of 50) to ratify — an extraordinarily high bar.

The last amendment ratified was the 27th (congressional pay raises) in 1992 — though it was originally proposed in 1789.

The Bill of Rights (amendments 1-10), the Civil War amendments (13th, 14th, 15th), and the voting rights amendments are the most consequential.

Multiple amendments are actively discussed — overturning Citizens United, establishing term limits, electoral college reform — but none are near the required threshold.

AI Summary

Key takeaways highlight Amending the Constitution requires either two-thirds of both houses of Congress AND three-fourths of states (38 of 50) to ratify — an extraordinarily high bar. The last amendment ratified was the 27th (congressional pay raises) in 1992 — though it was originally proposed in 1789. The Bill of Rights (amendments 1-10), the Civil War amendments (13th, 14th, 15th), and the voting rights amendments are the most consequential. Multiple amendments are actively discussed — overturning Citizens United, establishing term limits, electoral college reform — but none are near the required threshold.

The United States Constitution is one of the world's oldest functioning written constitutions. It has endured for 235 years, governing a country that has transformed beyond any recognition by the Founders who wrote it.

It has been formally amended 27 times. For perspective: the UK has an uncodified constitution that evolves continuously through parliamentary legislation. India has amended its constitution over 100 times. The US's 27 amendments in 235 years reflects a framework so difficult to change that it survives partly through reinterpretation rather than formal revision.

The Intentionally High Bar

The amendment process was designed to be hard. The Founders had just lived through a period of constitutional instability and wanted the fundamental law to be resistant to temporary majorities or political passions.

The standard process: two-thirds of both houses of Congress must approve the proposed amendment, then three-fourths of state legislatures (currently 38 of 50) must ratify it.

Two-thirds of the House means 290 votes. Two-thirds of the Senate means 67 votes. Then 38 state legislatures must independently pass the amendment.

In an era where the two parties disagree on virtually everything and neither routinely holds two-thirds of either chamber, this threshold is nearly impossible for anything politically contested.

The Amendments That Changed America

The Constitutional amendments can be divided into clusters:

The Bill of Rights (1-10, 1791): Guarantees the freedoms from government that we most associate with American identity — speech, religion, press, assembly, arms, unreasonable search, due process, jury trial. Added to secure ratification of the original Constitution by skeptical states.

Civil War Amendments (13, 14, 15): Abolished slavery (13th), established equal protection and due process and citizenship for formerly enslaved people (14th), prohibited denial of voting rights based on race (15th). These three amendments transformed the Constitutional framework more than any others and continue to be the basis for most civil rights law.

Progressive Era Amendments (16, 17, 18, 19): Authorized the income tax (16th), established direct election of senators (17th, replacing legislative appointment), prohibited alcohol (18th — later repealed by the 21st), and gave women the right to vote (19th).

Voting Rights Amendments (23, 24, 26): Gave DC residents Electoral College votes (23rd), abolished poll taxes in federal elections (24th), lowered the voting age to 18 (26th).

The Failed Amendments

Hundreds of amendments have been proposed and never ratified. The most notable failures:

Equal Rights Amendment (ERA): Proposed in 1972, guaranteeing legal equality regardless of sex. Required ratification by 38 states. Reached 35 ratifying states quickly, then stalled. Nevada (2017), Illinois (2018), and Virginia (2020) eventually became states 36, 37, and 38 — but decades after Congress's ratification deadline. Whether the belated ratifications count is actively litigated.

DC Voting Rights Amendment: Proposed in 1978, would give DC voting representation in Congress. Ratified by only 16 states before the deadline lapsed.

Balanced Budget Amendment: Has passed both houses at various times but never with two-thirds majorities simultaneously and never reached state ratification. Proposed by Republicans in almost every Congress, used more as messaging than serious constitutional effort.

What the Current Debates Reveal

The most discussed constitutional changes today — overturning Citizens United through amendment, term limits, electoral college reform — all share one feature: they would require the cooperation of the institutions they are designed to reform.

The Supreme Court justices who issued Citizens United would need to be replaced before their successors would voluntarily overturn it through case law. The senators who benefit from the current system would need to vote for their own term limits. The states that benefit from the Electoral College (small states, battleground states) would need to ratify its elimination.

This is the fundamental constraint: constitutional change requires either bipartisan supermajority support or such overwhelming national consensus that partisan resistance becomes untenable.

In an era of high polarization, the 27th Amendment may be the last for a generation.

FAQ

How do you amend the Constitution?

There are two methods. Method 1 (used for all 27 amendments): Congress proposes an amendment by two-thirds vote of both the House and Senate, then three-fourths of state legislatures (38 of 50 states) ratify it. Method 2 (never used): Two-thirds of states call a constitutional convention, which proposes amendments that must then be ratified by three-fourths of states. The high threshold is intentional — the Founders wanted fundamental law to be stable and not subject to simple majority whims.

How many amendments does the Constitution have?

The Constitution has been amended 27 times. The first 10 amendments — the Bill of Rights — were ratified together in 1791 as a package. The most recent amendment (27th) was ratified in 1992, prohibiting laws varying congressional compensation from taking effect until after an election. The 27th Amendment was originally proposed in 1789 and remained pending for 203 years before enough states ratified it.

What are the most important Constitutional amendments?

The most consequential amendments: 1st Amendment (speech, press, religion, assembly — 1791), 13th Amendment (abolished slavery — 1865), 14th Amendment (equal protection, due process, citizenship — 1868), 15th Amendment (Black men's right to vote — 1870), 17th Amendment (direct election of senators — 1913), 19th Amendment (women's right to vote — 1920), 24th Amendment (abolished poll taxes in federal elections — 1964), and 26th Amendment (voting age to 18 — 1971).

What amendments are being proposed today?

Active amendment proposals include: overturning Citizens United (reversing the campaign finance ruling), establishing term limits for Congress and/or the Supreme Court, abolishing or reforming the Electoral College, a balanced budget amendment (requiring Congress to balance the federal budget), and codifying specific rights (Equal Rights Amendment for gender equality has been ratified by the required states but faces legal questions about the deadline). None are currently near the two-thirds congressional threshold required to move forward.