President Bush's call for a constitutional amendment to define marriage as being only between a man and a woman faces a long and difficult path to become reality. Here's a look at the process the president must go through to legally amend the Constitution:
Q: How can the Constitution be amended?
A: A two-thirds majority of both the House and the Senate needs to pass the amendment, which is then sent to the states for ratification. It must be approved by three-fourths — 38 — of the 50 states. Congress normally will set a time limit, typically seven years, for the states to act.
The Constitution allows for a second method of amendment, which has never been used. Two-thirds of the state legislatures would call for a Constitutional Convention (search) where amendments would be proposed, then sent to the states for approval.
The methods whereby states ratify amendments vary. Many state legislatures require approval by "constitutional majorities"— a majority of the membership of the legislature. Some require ratification by the same margin as proposed amendments to their state constitutions; others only require a majority of the legislators present and voting.
At least seven states — Alabama, Colorado, Delaware, Georgia, Idaho, Illinois and Kansas — require a "supermajority" vote (search) in one or more chamber by rule, statute or state constitution.
A president can veto neither an amendment proposal nor a ratification.
Q. Can the Constitution be changed another way?
A. The Constitution's meaning can be changed over time via an "informal amendment." This can occur when circumstances change — for example, when the voting age was lowered from 21 to 18 — or through the judiciary, the ultimate arbiter of how the Constitution is interpreted. One judge's ruling can change how the Constitution is read.
Q. How many amendments to the Constitution have there been?
A. There have been 27 amendments to the Constitution to date. The first 10 comprise the Bill of Rights (search). The 21st amendment repeals the 18th, which banned the sale of alcohol in the United States. The 27th amendment, proposed in September 1789 but not passed until May 1992, says no law changing the compensation for U.S. senators and representatives shall take effect until lawmakers have a say.
Q. What are some amendments that have been proposed in Congress but not passed?
A. 2003-04 congressional session: To guarantee the right to use the word "God" in the Pledge of Allegiance (search) and the national motto; to restrict marriage in all states to be between a man and a woman; to remove protections for child pornography; to allow Congress to pass laws for emergency replenishment of its membership should more than a quarter of either house be killed; to place presidential judicial nominees immediately into position, providing the Senate with 120 days to reject the nominee.
2001-02 congressional session: To repeal the 8th Amendment (search), which prohibits excessive bail, excessive fines and cruel and unusual punishment, and replace it with a clause barring incarceration for minor traffic offenses; a right to "equal high quality" health care; to limit pardons granted between October 1 and January 21 of any presidential election year; to allow for any person of age, regardless of birth, who has been a citizen of the United States for 20 years or more to be eligible for the presidency.
Q. What are some amendments that failed to be ratified by the states?
A. 1810: Any citizen who accepts or receives any title of nobility from a foreign power or accepted a gift from a foreign power without congressional consent would no longer be a U.S. citizen and therefore could not hold public office.
1861: No amendment shall be made to the Constitution which will authorize or give to Congress the power to abolish or interfere, within any state, with domestic institutions, including slavery.
1926: Congress can limit, regulate and prohibit child labor of persons under 18 years of age.
1972: Women and men should be seen as equals under the law.
1978: Would grant citizens of Washington, D.C., the same full representation in Congress as any state.
Sources: National Archives (http://www.archives.gov/federal_register/constitution/amendment_process.html),"Ratification of Amendments to the U.S. Constitution, Congressional Research Service, September 30, 1997) and www.usconstitution.net.