Senator Joseph Biden says he believes the Bush administration might have overstated the immediacy of an attack threat last week. Appearing on NBC's "Today" show, Biden said he saw no "hard evidence," nor did he see a "smoking gun." Biden is the ranking Democrat on the Senate Foreign Relations Committee. In television talk shows yesterday, White House officials said arrests and document seizures have derailed plans to attack the United States. Some of the surveillance intelligence dates back four years.