As Post #6 so cogently states, the Declaration of Independence is a marvelous document that does, indeed, include all that is necessary. The problem is within the citizenry. As Pericles declared, "Democracy by its very definition is doomed to failure. No government can satisfy the wants of each man's stomach."
When the Patriot Act was passed, it was a previously failed act that had been renamed so it would sound favorable. In the wake of 9/11 people relinquished some their First Amendment rights in the interest of "safety." From this first step, quelling dissenters from the opinions of those who control the media is just another step.
Besides, how would the writers of the Declaration ever imagine "political correctness" as anything possible in a free country?
I don't think there is anything left to add. The problem is not that the Declaration didn't say we had all the rights we needed, it's that it didn't suddenly make us into angels who would respect everyone else's rights. So we have slavery -- that's a clear violation of the right to liberty and the pursuit of happiness. If we don't protect free speech enough, that's an infringement on liberty. There are no rights that would not fall under one of these categories.
I agree that I would perhaps have spelled out some of the included rights a little more clearly. As post 2 suggested, we now include everyone in the definition of people and this was not necessarily the case when the Declaration was written. Through the years, we have changed how we interpret the ideals listed in the Declaration. It would have nice to have things a little more clearly spelled out. For instance, at what point do we allow one person's freedoms to hinder another person's freedoms? As post 4 suggested, this is sometimes the case with the freedom of speech. Everyone should have the right to free speech. Everyone also has the right to disagree or choose not to listen. We need to take a closer look at the difference between protect and censorship when it comes to the rights set forth in the Declaration of Independence, the Constitution, and the Amendments.
Check this out:
As far as adding rights goes, I think we have a process for that in the court system. The whole purpose of arguing interpretations of the Constitution is to figure out which behaviors, lifestyles, and ideologies are Constitutionally permitted. This is not to say that anything not formally allowed should be banned (although we have done just that as a nation for centuries), but we should always check the words and history of the Constitution to see if something is already covered.
I guess the only thing I would add is a stronger defense of free speech. There is a movement in the U.S. now to stifle anything that doesn't fit the cultural norm -- even if that norm has changed to allow things that were previously seen as immoral or indecent! The right to free speech is not a right to be heard, and so is also not a right to stifle anyone who offends. The people we disagree with must be allowed their voice, or we risk the public and accepted return of institutionalized censorship.
I agree with # 2. The United Nations Universal Declaration of Human Rights is an interesting document with which to compare the U. S. Declaration of Independence. It, for instance, specifies a right to be free from slavery, and certainly it would have been helpful if this right had been made explicit in the Declaration. The word "liberty" might seem to imply liberty from slavery, but obviously the Declaration did not prevent slavery from being practiced in the U. S. -- perhaps the greatest stain on our nation's history.