From Founding Fathers:
The Congress, whenever two thirds of both Houses shall deem it necessary, shall propose Amendments to this Constitution, or, on the Application of the Legislatures of two thirds of the several States, shall call a Convention for proposing Amendments, which, in either Case, shall be valid to all Intents and Purposes, as Part of this Constitution, when ratified by the Legislatures of three fourths of the several States, or by Conventions in three fourths thereof, as the one or the other Mode of Ratification may be proposed by the Congress; Provided that no Amendment which may be made prior to the Year One thousand eight hundred and eight shall in any Manner affect the first and fourth Clauses in the Ninth Section of the first Article; and that no State, without its Consent, shall be deprived of its equal Suffrage in the Senate.Basically, the Article 5 says that Congress can call for Amendments with a 3/4 vote, and states can call for a convention with 2/3 of the legislatures voting in approval. So if 34 states vote for a convention, we get one.
To determine what this means, we have to consider the history of the creation of the Constitution.
First, there were the Articles of Confederation.
The Articles of Confederation created a loose collection of existing states where almost all of the power was retained by the states. There was a weak, delegate filled congress, and it's purpose was to provide a single face to the world at large, and maintain good relations between states. The AoC was completely unconcerned with the government of people, except that it defined the relationships between the states themselves. There was no statement of rights because that was a state issue.
Many statesmen, including George Washington, became concerned that the idea of a strong "America" was becoming lost in the states refusal to comply with the Articles. The states were passing abusive laws and infringing on the rights specified in the Declaration of Independence. There were several attempts at amendments to the Articles, but due to the requirement of 100% states' approval, none passed. In 1786, James Madison suggested that the Virginia Legislature invite all states to discuss commerce, and during this "commission," a motion was endorsed to create a "Grand Commission" in Philadelphia in May, 1787. The purpose of this convention was to determine ways to improve the Articles.
The first thing that was done was the decision to work in secret, and the second decision was to basically invalidate the Articles of Confederation.
Of course, this turned out to be a good thing. The AoC were weak and would not have been able to hold the states together. The end result would have been multiple country-states and the failure of the great American Experiment. The document we ended up with was a compromise between hard-core federalists like Alexander Hamilton and hard-core anti-federalists (state-based government only) like Patrick Henry (who declined to attend, but was vehemently opposed to a strong federal government).
While I may write an essay, one day, on the convention itself, suffice it to say that over the course of four months, the Constitution was written. It was a collection of procedures and powers specifically granted to the newly created federal government. It laid down the structure of government, created all three branches of government, the procedures for elections, and most everything necessary to run this new federal government.
After it was approved by the convention, the battle for ratification began. Of course, Madison, Hamilton and Jay wrote the Federalist Papers in support, and Patrick Henry and various others produced the Anti-Federalist papers against. After the convention, George Mason, one of the convention members, became one of its biggest opponents because, "It has no declaration of rights." After quite a bit of debate, James Madison crafted the Bill of Rights, which was ratified along with the constitution.
The purpose of this very brief history of the Constitutional Convention of 1787 is to illustrate what can be accomplished by such an assemblage of people. The delegates to this Grand Convention were tasked with modifying the Articles of Confederation, and instead decided that the existing documents did not provide the appropriate government to maintain the "more perfect Union." The delegates were all established, well respected statesmen, and most had been involved in the war of Independence. They had seen the face of tyranny and understood what would be necessary to prevent it.
So if there were a "Great Convention" today, who would you send to it? There are no restrictions on how the delegates are selected. Congress determines how the delegates are chosen. Would Congress elect the delegates? The State Legislatures? Would there be a vote of the people to determine the delegates from each state? Would the people be involved at all? What great statesmen exist today that you would trust with the recreation of The Constitution of the United States of America? Could such a document even be created today?
Since Article 5 does not put any real restrictions on what can be done in a Con-Con, one simple amendment could be proposed or, as before, the entire Constitution could be thrown out. The convention could have almost limitless power. Congress and the president could place no restrictions on this group of people. They could propose whatever they wanted.
According to the existing constitution, a vote of 3/4 of the states' legislatures can approve an amendment. While I have difficulty believing that it's possible for the entire Constitution to be invalidated, with the political environment today, it is not difficult to imagine a convention that removes some of the more "troubling" provisions of the constitution. Article 2? Freedom of speech? The individual right to bear arms? The prohibition of search and seizure? The assignment of powers to the states? All of those have been challenged recently and would certainly be targets of this new, modern day Con-Con.
Changing the distribution of powers between the branches of government, consolidation of federal powers, submission to world organizations, a fully federalized system, the constitutional establishment of welfare programs and distribution of wealth, creation of new "rights"; all of these could be included. One would have to be daft to think that the process wouldn't be affected or influenced by the political lean of the current administration.
Already there have been multiple infringements on the rights laid out in the Bill of Rights: unchallenged but unconstitutional laws passed by congress, unconstitutional rulings by courts all over the country and presidential edicts that push the limits of the law. None of these can hold the proverbial candle to what a new Con-Con could create. Of course, the new documents would have to be ratified, but as the original Con-Con changed those rules from 100% to 75% of states required for ratification. This new Con-Con could change the ratification requirements to suit its particular purpose.
Given the current political climate, and without any real way to limit the scope or purpose of a new Constitutional Convention, creating a new convention would be incredibly unwise. While the language of the current Constitution could certainly be considered antiquated, the principles put forth are far from it. They are more relevant today than ever before. History may well consider the Constitution and Bill of Rights to be two of the most important documents ever written. Discarding them now could very well be the beginning of the death of these United States of America.
Edit: Even I can get confused. Replaced "5th Amendment" with "Article 5" twice at the beginning of the essay.