How did the USA PATRIOT Act expand the power of U.S. law enforcement to monitor computer networks?

The USA PATRIOT Act, signed into law in 2001, significantly expanded the authority of U.S. law enforcement to monitor computer networks and electronic communications by amending existing statutes such as the Wiretap Act.12

Key provisions that increased surveillance capabilities included:

• Expanded Eavesdropping: Sections 201 and 202 added computer and terrorist crimes to the list of serious offenses for which law enforcement could obtain a court order to conduct electronic eavesdropping.1
• Trap-and-Trace and Pen Registers: Section 216 permitted the use of these devices to monitor electronic communications, including e-mail and Web browsing. These orders did not require probable cause, only a government certification that the information was relevant to a criminal investigation.1
• Roving Surveillance: Section 206 allowed the Foreign Intelligence Surveillance Court (FISC) to authorize "roving" electronic surveillance, which could be applied to any location or equipment.1
• Access to Records: Section 210 allowed authorities to obtain subscriber credit card or bank account numbers via subpoena, while Section 215 granted broad authority to demand "any tangible things" from third parties.1

These measures were intended to enhance national security, though they faced significant criticism for potentially infringing upon privacy and constitutional rights.13