By any reading of the plain words of the Constitution, which is not how contemporary jurists read the Constitution, the Patriot Act is unconstitutional and should be repealed. From Andrew P. Napolitano at lewrockwell.com:
I have been writing for years about the dangers to human freedom that come from government mass surveillance. The United States was born in a defiant reaction to government surveillance. In the decade preceding the signing of the Declaration of Independence, the villains were the Stamp Act and the Writs of Assistance Act. Today, the villain is the Patriot Act.
Here is the backstory.
In 1765, when the British government was looking for creative ways to tax the colonists, Parliament enacted the Stamp Act. That law required all persons in the colonies to purchase stamps from a British government vendor and to affix them to all documents in one’s possession. These were not stamps as we use today, rather they bore the seal of the British government. The vendor would apply ink to the seal and for a fee — a tax — impress an image of the seal onto documents.
All documents in one’s possession — financial, legal, letters, books, newspapers, pamphlets, even posters destined to be nailed to trees — required the government stamps.