Tim Weiner, author of "Enemies: A History of the FBI" and "Legacy of Ashes: The History of the CIA" explains how terrorist threats are identified, and how information is, or is not shared across federal agencies.

At his Senate confirmation hearing yesterday, John O. Brennan tried to restore Americans' faith in the C.I.A. While Brennan expressed his disapproval for torture, he staunchly defended the C.I.A.'s drone program.

Former CIA Director David Petraeus resigned on Friday, hoping to get in front of the scandal involving Paula Broadwell before it thrust him any further into the spotlight. But Congress has other ideas. Tim Weiner has covered the CIA for The New York Times and is the author of, "Legacy of Ashes: The History of the CIA."

Charles W. Colson, Watergate mastermind turned Evangelical leader, died of a brain hemorrhage on Saturday at the age of 80. Colson, special counsel to the Nixon Administration, served seven months for obstruction of justice in the Watergate scandal. But Colson emerged from prison a born-again Christian, promising to devote his life to religious activities. And though he may be remembered most for his role in Watergate, Tim Weiner, journalist and author of "Enemies: A History of the FBI," believes that Colson's true legacy might be his role in forging alliances between Evangelical Protestants and Catholics to create the religious wing of the Republican Party.

Eleven Secret Service employees are accused of bringing prostitutes back to their hotel in Cartagena ahead of President Obama's visit for a summit in Colombia. The agents and officers have been placed on leave while the agency investigates their conduct. Although prostitution is legal in parts of Colombia and no law was broken, if the reports are true, the employees still violated rules of conduct. Tim Weiner, author of "Enemies: A History of the FBI," has won the Pulitzer Prize and the National Book Award for his work on national security. Weiner explains what happened and why the employees' alleged indiscretions could have put the President Obama's life at risk.

Since its founding, the Federal Bureau of Investigation has grappled with how to balance personal liberty and national security. The bureau grew exponentially in the years following World War I, as the country became increasingly terrified by the communist threat. The fear of communism often served as a guide for J. Edgar Hoover, the man who built the FBI and ran the Bureau for more than 40 years.