Many of the programs supported by the increase in intelligence funding remain secret.
But since the 9/11 attacks, the federal government has accumulated a host of new or extraordinary powers in the name of counterterrorism.
One example is the use of what the FBI calls “national security letters,” which are administrative subpoenas for records that do not require probable cause or a warrant signed by a judge.
These letters have been used to obtain phone records from telecommunications companies, websites visited by individuals from Internet service providers and financial records from businesses.
According to the Justice Department’s inspector general, the FBI issued 193,099 such letters from 2003 to 2006.
Restrictions on when the National Security Agency can wiretap or sort through telephone and Internet traffic have also been eased.
In 2005, the New York Times exposed a top-secret program authorized by President Bush aimed at monitoring electronic communications between terrorists abroad and people in the United States.
Though the story and the program elicited strong criticism from many Democrats and others including then-Sen. Barack Obama voted to enshrine those powers into law in 2008 in amendments to the Foreign Intelligence Surveillance Act.
Another example of expanded law enforcement authority is the USA Patriot Act, which was signed into law just six weeks after the 9/11 attacks.
The most significant portions of the law allow the FBI to renew surveillance of individuals even if they switch phones, creating a “roving wiretap” and eliminating an old requirement to ask a court to issue new warrants for new phone numbers.
The legislation also removed a legal wall that separated domestic law enforcement investigations from intelligence-related investigations.
In May, a Wired magazine interview with Sen. Ron Wyden, Oregon Democrat, first disclosed that the federal government has a “secret interpretation” of the Patriot Act.
“I draw a sharp line between the secret interpretation of the law, which I believe is a growing problem, and protecting operations and methods in the intelligence area, which have to be protected,” Mr. Wyden said.
Jameel Jaffer, a senior attorney at the American Civil Liberties Union who litigated the first successful court challenge on the Patriot Act, said he suspects the secret interpretation of the law lets the FBI track the locations of suspects through their cellphones.
“My educated guess is that the FBI is using the Patriot Act to engage in suspicionless location tracking, not just of suspected terrorists, but of innocent people as well,” he said.