The Amendment Process
There are essentially two ways spelled out in the Constitution for how it can be amended. One has never been used.
The first method is for a bill to pass both halves of the legislature, by a two-thirds majority in each. Once the bill has passed both houses, it goes on to the states. This is the route taken by all current amendments. Because of some long outstanding amendments, such as the 27th, Congress will normally put a time limit (typically seven years) for the bill to be approved as an amendment (for example, see the 21st and 22nd).
The second method prescribed is for a Constitutional Convention to be called by two-thirds of the legislatures of the States, and for that Convention to propose one or more amendments. These amendments are then sent to the states to be approved by three-fourths of the legislatures or conventions. This route has never been taken, and there is discussion in political science circles about just how such a convention would be convened, and what kind of changes it would bring about.
Regardless of which of the two proposal routes is taken, the amendment must be approved by three-fourths of states. The amendment as passed may specify whether the bill must be passed by the state legislatures or by a state convention. See the Ratification Convention Page for a discussion of the make up of a convention. Amendments are sent to the legislatures of the states by default. Only one amendment, the 21st, specified a convention. In any case, passage by the legislature or convention is by simple majority.
It is interesting to note that at no point does the President have a role in the formal amendment process (though he would be free to make his opinion known). He cannot veto an amendment proposal, nor a ratification.
"Informal Amendment"
Another way the Constitution's meaning is changed is often referred to as "informal amendment." This phrase is a misnomer, because there is no way to informally amend the Constitution, only the formal way. However, the meaning of the Constitution, or the interpretation, can change over time.
There are two main ways that the interpretation of the Constitution changes, and hence its meaning. The first is simply that circumstances can change. One prime example is the extension of the vote. In the times of the Constitutional Convention, the vote was often granted only to monied land holders. Over time, this changed and the vote was extended to more and more groups. Finally, the vote was extended to all males, then all persons 21 and older, and then to all persons 18 and older. The informal status quo became law, a part of the Constitution, because that was the direction the culture was headed. Another example is the political process that has evolved in the United States: political parties, and their trappings (such as primaries and conventions) are not mentioned or contemplated in the Constitution, but they are fundamental to our political system.
The second major way the meaning of the Constitution changes is through the judiciary. As the ultimate arbiter of how the Constitution is interpreted, the judiciary wields more actual power than the Constitution alludes to. For example, before the Privacy Cases, it was perfectly constitutional for a state to forbid married couples from using contraception; for a state to forbid blacks and whites to marry; to abolish abortion. Because of judicial changes in the interpretation of the Constitution, the nation's outlook on these issues changed.
In neither of these cases was the Constitution changed. Rather, the way we looked at the Constitution changed, and these changes had a far-reaching effect. These changes in meaning are significant because they can happen by a simple judge's ruling and they are not a part of the Constitution and so they can be changed later.
Source: The U.S. Constitution Online (11/24/2004) © 1995-2003 by Steve Mount. All rights reserved.