You'll have to forgive me. I have been reading the "Heritage Guide to the Constitution" (published by the Heritage Foundation), and so it may culminate in a number of Constitution based articles as I work my way through this highly recommended publication.

One of the arguments I have heard lately on talk radio and conservative print media sources is that the right to the "pursuit of happiness" is not in the Constitution, and thus, not a right guaranteed to all Americans.

They're right on the first count, wrong on the second. You see, the reason the right to "the pursuit of happiness" is not in the Constitution is expressly stated in another foundation document, the Declaration of Independence. The right to pursuit of happiness was held to be "self evident" (meaning even a dummy should be able to sort it out), and we were ENDOWED with these rights by our creator. This meant that a legitimate government did not have legitimate authority to remove these rights without a damn good reason (or, "due process" in more genial legal terms).

It was on this basis that the Bill of Rights was authored. Many founding fathers refused to sign without a Bill of Rights, because they knew that "life, liberty and the pursuit of happiness", while understood by them, was a very vague and ambiguous basis from which to make legal decisions. Better to spell out some of the rights that those words entailed.

A myth that revolves around these rights is that they are GIVEN us by the government. The founding fathers did not believe this, but rather believed these rights to be our birthright, given us by our Creator (sorry, Mr. Newdow), and the language of the Constitution does not give the government permission to assign these rights but rather forbids them permission to infringe upon them. While the pursuit of happiness is not among those enumerated, its presence in the Declaration make it clear that it is an intended right granted us by God.