General Clapper has had a lifetime of honorable service to the US in every major intelligence position. You ask, "Wasn't it Clapper's job to stop them?" The FBI and CIA were then investigating the hacking of DNC and RNC servers. Clapper was certainly aware of that, and aware that the FBI and CIA were the appropriate entities to do the investigation. Contrast that with the Trump firing Comey obviously for testifying on the ongoing investigation. It seems clear that Trump is attempting to shut down the investigation, or derail it.

In testimony before the Senate Intelligence Committee, Clapper was given the questions in advance. The question he was given was,