The U.S. Congress provides this opportunity by voting 227 to 183 to approve this legislation.
U.S. President Bush White House announcement
Washington Post article:
Senate Votes To Expand Warrantless Surveillance
The Senate bowed to White House pressure last night and passed a Republican plan for overhauling the federal government's terrorist surveillance laws, approving changes that would temporarily give U.S. spy agencies expanded power to eavesdrop on foreign suspects without a court order.
(By Joby Warrick and Ellen Nakashima, The Washington Post)
New York Times article:
Bush Signs Law to Widen Legal Reach for Wiretapping
By JAMES RISEN
People familiar with the law said that it provided a legal framework for much of the surveillance without warrants that was being conducted in secret.
Bush Signs Law to Widen Reach for Wiretapping
While such warrant less surveillance is framed in the context of suspected "terrorists" and of involving only communications with a least one foreign participant, nothing is said about oversight to guard against its abuse to stifle/discourage peaceful dissent.