President Bush has signed a renewal of the USA Patriot Act and hailed it as vital to the war on terrorism.
Passage had been blocked for months by a battle with Congress over how to balance Americans' right to privacy with a need to foil security threats in the aftermath of the September 11th attacks that gave rise to the original Patriot Act.
The White House won approval from lawmakers after agreeing to revisions along with a companion bill that sponsors said would better protect civil liberties under the act.
The bill reached President Bush's desk as 16 major provisions of the old law were due to expire today.
The White House signing ceremony came against the backdrop of a move to end a political storm over Mr Bush's support for a state-owned Arab company taking over US port operations.
Dubai Ports World pledged yesterday to transfer operation of six US port terminals to a US entity, a move the White House said should settle the controversy surrounding the deal.
Critics had pointed to the contrast between Mr Bush's hawkish stance in his push for the Patriot Act's extension and what they saw as a lax view of security risks in the ports deal.
Enacted shortly after the 2001 attacks on New York and Washington, the Patriot Act expanded powers to obtain private records, conduct wiretaps and searches and share information. Critics said it went too far in infringing on basic rights.
His signature made 14 of the Patriot Act's provisions permanent and extended two others by four years. He said renewal allowed law enforcement to continue "pursuing terrorists with the same tools they use against other criminals".