Infringing on rights, whether legally or not is a restriction on rights. Some restrictions are moral (prohibition of child porn, perjury) and some are not (McCain/Feingold) but they are an infringment or restriction nonetheless.
I agree, but one right you do not have is to infringe upon the rights of another.
This is really a simple concept that I am shocked you don't understand: Rights are not absolute. The state can legally and morally restrict your rights if they infringe on the rights of other.
That is correct - they can. Up until the point that you violate the rights of another person, your rights ARE absolute. The examples you gave (perjury and child pornography) are not an exercise of your rights, but the violation of another's rights. Hence the punishment.
Tell me, do you believe you have an absolute freedom of speech under the US Constitution?
Trick question. The literal answer is no, but not for the reason you might think. The Constitution does not grant me any rights. It recognizes my existing ones and charges government with safeguarding them.
To answer the question i think you intended to ask, yes, the Constitution DOES prohibit Congress from applying any restrictions to my speech.
In no way does this mean that I cannot face legal action for violating the rights of another person. Speech which violates another's rights may be criminally actionable
With all that being addressed, exactly how does any of this justify the search of someone merely because they have entered a building in which they are legally permitted, and in some cases, obligated to be?
You're kidding right. If the right has a point it can no longer be exercised, it cannot be absolute. You aren't really that dense, are you?
The Constitution does not grant me any rights. It recognizes my existing ones and charges government with safeguarding them.
That why I wrote "under" the constitution, not "provided" by it.
To answer the question i think you intended to ask, yes, the Constitution DOES prohibit Congress from applying any restrictions to my speech.
Then the laws against perjury (a restriction, albeit a reasonable one, on speech) in federal courts would be unconstitutional? Before you answer, let me give you the answer. No, a law restricting your freedom of speech to prevent you from committing perjury is not unconstitutional, even though it is a law passed by Congress, and it restricts your speech.