Saving Government from the Scourge of Morality, and the Controversy of Same-Sex Marriage
Although philosophical traditions of rationalism and the enlightenment have appropriately gone by the wayside, essential contributions still remain. Among these is the theory of the social contract, which argues for a government that exists solely because the people created it and ceded certain powers to it out of necessity. This contract, which forms the basis of our government, therefore seems to imply that the intrusion of this government into the lives of the people should be kept to a necessary minimum. Defining what constitutes a "necessary" minimum is the focus of many policy debates over a broad spectrum of issues. The recent attempt of the Congress to place a constitutional amendment on same-sex marriage is a clear and dangerous violation of the principles of limited government. As is (or shall hopefully become!) apparent, issues of pure morality such as same-sex marriage are wholly outside the legislating powers of Congress, and they are a breach of the social contract which we possess with our government.
The social contract gives the government the power to do what is necessary to protect the population it governs. It therefore logically follows that morality is a breach of this contract. The obvious counter to this averment is that the government must necessarily enforce morality because all belief is derived from it: if the government were to not enforce the beliefs of its constituancy then it would not exist. Cynics would immediately point out that murder is derived from the moral belief in everyone's right to live. Murder and the abuse of other humans is the fundamental reason why the social contract exists. However, all morality it not created equal. The morality that the government does have the power to enforce is that which is necessary for the preservation of life, liberty, and property [and happiness; many thanks to Mr. Franklin]. While banning murder is an example of a moral belief, the government has every right to enforce it since it is required for the population to exist peacefully and happily. Therefore, a consequence of the social contract theory is that the government must rationally link every action it makes, whether based in morality or not, to a tangible need of society. Petty whims of moral belief that are not grounded in a scientific reasoning, such as prayer, cannot be made manditory. However, since restricting prayer would be an infringement upon the liberty of the people, and since there is no tangible and rational basis for doing so, the social contract does not give the government the authority to ban it. In the US, the Constitution provides the basis for our laws, but at the core of the Constitution rests many principles important to this contract.
Unfortunately, there are elements within our own society [to the right and the left] that attempt to crush this objective operation of the government. The foremost example of this, is the idiotic move to create an constitutional amendment against same-sex marriage. A vote was recently held in the House, which failed the necessary 2/3 majority to propose the amendment, but it was still a surprising (to me) majority of 227-186. The support for this amendment is almost entirely based around the idea that same-sex relations are traditionally immoral. The only tangible argument, which would give the necessary perogative for the government to restrict this freedom, is the nebulous point that same-sex marriage would destroy the traditional family unit and lead to social degradation. Aside from being vague, this argument is inherently weak. Banning same-sex marriage would give legal backing behind the social taboo against homosexuality. Lack of the acceptance of certain practices, beliefs, and conditions is what causes social degradation. Consider the AIDS epidemic. Before the disease was part of common discourse in society, people with the disease were often shunned and lost their dignity. As for the homosexuality debate, it is personal dignity which allows people to lead successful lives and form cohesive bonds with other people. The inclusion, not the exclusion of member of society is what helps to develop this dignity. It is presumptuous to claim that families with slightly different structure but equally strong values and dignity could not function as well as traditional families. On one last personal note, wide acceptance of homosexuality may also be a means of slowing population growth since two people of the same sex cannot procreate. : )
The entire debate has nothing to do with whether one agrees with the idea of homosexuality or not. It has to do with the preservation of the purpose of government as a contract of the limited secession of individual power to the government. It seems to me, that the one of the ultimate dangers to this idea is unchecked, irrational, and traditional morality. There's a reason why moving beyond good and evil may not entirely be such a poor or radical idea.

There are a few flaws in your reasoning. For example, the US Congress DOES have the power and right to legislate morality. Laws giving non-human and presumably non-sentient organisms rights exist.
In the second paragraph, it seems that the justification for banning murder could apply just as well to gay marriage. Large segments of the population currently feel threatened by gay marriage and some have commited acts of violence to demonstrate their opposition. By this "social contract" theory, the Congress CAN legislate against gay marriage because gay marriage is threatening the population's happiness and peacefulness.
It's threatening their perceived happiness, not their physical, economic, or tangible welfare.
So you equate happiness with tangible welfare?
Have you any response to animal rights?