The Fourth Amendment protects US citizens from unreasonable search and seizure. Clearly that is being violated as the recent ruling on NSA data collection has pointed out.
As are you and I. You can't be retroactively convicted of a crime if it was not against the law at the time.
>No person shall be held to answer for a capital, or otherwise infamous crime, unless on a presentment or indictment of a Grand Jury, except in cases arising in the land or naval forces, or in the Militia, when in actual service in time of War or public danger; nor shall any person be subject for the same offence to be twice put in jeopardy of life or limb; nor shall be compelled in any criminal case to be a witness against himself, nor be deprived of life, liberty, or property, without due process of law; nor shall private property be taken for public use, without just compensation
>In all criminal prosecutions, the accused shall enjoy the right to a speedy and public trial, by an impartial jury of the State and district wherein the crime shall have been committed, which district shall have been previously ascertained by law, and to be informed of the nature and cause of the accusation; to be confronted with the witnesses against him; to have compulsory process for obtaining witnesses in his favor, and to have the Assistance of Counsel for his defence.
>Excessive bail shall not be required, nor excessive fines imposed, nor cruel and unusual punishments inflicted
In other words, clearly, The Fourth Amendment does NOT protect anyone from NSA's violations.
There are not a "lot of unconstitutional practices" that are law in the U.S. There are a lot of people who read the words in the Bill of Rights extremely broadly and without historical or legal context, and then put up poorly-designed web pages about all the "unconstitutional" things they have discovered.
If anything, the last 15 years has shown me that 'anything' is possible.
So is warrant-less wiretapping, but that didn't stop NSA.
There are two main problems with the United States, the first is that too many of us are ready and willing to trade personal freedom for economic and physical safety. The second is that we allowed money to control politics.
The only thing that's natural are the laws of nature, otherwise known as physics, and there is no law of physics that prevents me from torturing someone.
Good thing I didn't imagine the idea of rights would physically prevent you from torturing someone. Basically, rights are an idea meant to help us in drawing boundaries between what's acceptable behaviour and what's not. But it's got nothing to do with the government, and everything to do with reason, logic, consistency and common sense. A government or a piece of paper can't grant any rights or take any away, and in fact, governments only violate our rights.
Ex post facto laws are unconstitutional in the US.