President Bush wants to make the USA Patriot Act permanent, but as the ACLU points out, some of the provisions of that law are unnecessary and unconstitutional:

Among the provisions of the Patriot Act scheduled to sunset is the controversial Section 215, which allows the FBI to obtain orders for the production of any “tangible things” (which can include library, travel, genetic, health, business or firearms records) without any meaningful standard of judicial review and no mechanism for the person affected to challenge the order.
This provision has been challenged by the ACLU in a federal lawsuit as violating Americans’ First, Fourth and Fifth Amendment rights. Last year, Attorney General John Ashcroft said Section 215 has not been used, raising the question of why the Bush Administration believes such sweeping law enforcement powers are essential for the war on terrorism.

As this recently-revealed incident highlights, one of the most effective defenses against terrorism is something much simpler than a complex network of government snooping:

A month before the Sept. 11, 2001, attacks, U.S. Customs officials at an airport in Orlando refused entry to a young Saudi man who authorities now suspect may have been arriving to meet Mohamed Atta, leader of the suicide hijacking plot, government sources said yesterday.
The man, identified only as “al Qahtani,” attempted to enter the United States in early August 2001, officials said, but was turned back by Customs officials, who grew suspicious when he said he planned to visit friends in this country but could not name them.

If true, this event illustrates that alert, front-line authorities with good instincts may be the best weapon to against terrorist plots. Recall that a 2000 terrorist attack was foiled when a suspicious-looking driver was apprehended at the Washington/Canadian border.
Instead of issuing the government permanent blanket authority to rummage through the private information of law-abiding Americans, we should be holding law enforcement and intelligence officials accountable in using the constitutional law enforcement tools they already have.