The U.S. Secret Service is under mounting pressure following two recent assassination attempts on former President and Republican candidate Donald Trump. On July 13, Trump was grazed by a bullet at a Pennsylvania rally, and on September 15, an armed attacker, Ryan Wesley Routh, came dangerously close to him with an AK-47. In this video, a former CIA officer breaks down why protecting Trump has become such a difficult and ‘impossible assignment.’ Watch for more.