Our DNI is on a 'No Need to Know' basis

Because Janet Napolitano and subordinates are on duty round the clock for 364 days a year as Homeland Security Chief honchos, James Clapper, Director of National Intelligence and the president's principal adviser, doesn't have to know everything; he certainly didn't have to know such trivial stuff that twelve terrorist wannabes had been rounded up in London. At least that's what Napolitano told Diane Sawyer on one of the Sunday talky talk shows.

I knew. [Chief Counterterrorism Advisor] John Brennan knew. We also knew there was no connect that had been perceived to anything going on in the homeland and that we were in perfect connectivity with our colleagues in Britain. So one of the things I think that should be very clear to the American people is that those of us in homeland security who needed to know, we knew.
In other words, the Director of National Intelligence and, by implication, the President of the United States didn't have to know about a near terrorist success story in an allied country. If that's true, why does this country have a Director of National Intelligence and a Homeland Security Secretary, and the CIA, and the FBI and all the other multiple layers of security and spying and intelligence? Do they communicate with each other somehow? Does the right hand know what the left foot is doing, let along the right and left brains?

Inquiring minds want to know, want to be safe.