Can one person oversee every spy?

Dennis Blair is spending his last day as director of national intelligence, but can one person be reasonably expected to oversee the US's huge intelligence apparatus?

Many people outside the US would know who the CIA and the FBI were. Some might even have heard of the NSA (National Security Agency), but the US has a host of intelligence entities beyond these three.

The US Navy alone has two agencies that deal with intelligence, the US Coast Guard has two more. The departments of Energy and Treasury both have their own intelligence services.

The sheer volume of agencies and the number of personnel working for them, both in gathering intelligence and analysing it, leave some pundits pessimistic about whether Mr Blair's successor - yet to be nominated by the president - can do his job well.

"As to having one person in control of all intelligence activity, I'm not certain that's possible," says Philip Mudd, former CIA and FBI analyst and senior research fellow at the New America Foundation.

"There are something like 17 intelligence agencies - army intelligence and navy intelligence and so on.

"To expect that one person can have enough of a pulse on these agencies to be the responsible party when there is a perceived gap, as we saw on the 25 December incident [alleged attempt to blow up a Northwest Airlines flight by Umar Farouk Abdulmutallab], is not realistic."

The post of director of national intelligence was created in the wake of the 9/11 Commission's recommendations in 2004. The aim was to make sure that the US's different intelligence agencies shared information and co-ordinated their efforts properly.

But some see the fact that there have been three directors already as showing that the post has not worked out.

"He has no power, no leverage. He can't make anything happen. He doesn't control anything of significance in the [intelligence] community," says Mark Lowenthal, former deputy assistant secretary of state for intelligence and president of the Intelligence and Security Academy.

"He is just there to try and get people to listen to him and co-ordinate. He can't. I think we have proved that to everyone's satisfaction."

The intelligence services - and by extension Mr Blair - came under criticism for the alleged Christmas Day plot, and even for the failed Times Square bomb attack.

In a recent statement, Mr Blair admitted: "Institutional and technological barriers remain that prevent seamless sharing of information."

Mr Blair himself was reported to have clashed with CIA chief Leon Panetta about the appointment of intelligence representatives around the world.

"Many will watch closely whether the person is a professional intelligence officer or an outsider, someone who has political connections that might give him or her more authority to try to assume a directive role," says Mr Mudd.

"If you want the individual to break heads, it is hard to find somebody from within professional intelligence who can do that."

One option would simply be to abolish the post.

"You could also get rid of it, which I think would be a more realistic situation, a better solution than the status quo," says Benjamin Friedman, research fellow in defence and homeland security at the Cato Institute think tank.

"But we never get rid of things in the US government. With bureaucracy there is birth but never death."

There is a case for returning to the structure that existed before Mr Blair's post was created, Mr Lowenthal suggests.

Then the job of co-ordinating the intelligence community fell to the director of central intelligence, who also ran the CIA.

"It worked better when the DCI [had the role]. He knew the analysts that produced the papers," says Mr Lowenthal, who was assistant DCI for analysis.

The other option would be to give the DNI control over every intelligence agency, control of budgets, control of strategy.

"There are those that see the DNI as an intelligence tsar, that he should be the boss of the whole effort and everybody should report to him," says Mr Richelson.

"That can only lead to a lot of infighting, a lot of tough hours and ultimately won't get done."

But is there an argument that - in the absence of major bomb attacks - US intelligence is actually performing fairly well?

"We have been very successful," says Mr Lowenthal. "The fact they are attacking in ones is a sign of success. The unspoken standard is perfection."

Part of the way intelligence is perceived may be influenced by the constant stream of fictional portrayals - like the Bourne trilogy and a slew of others.

"There is unreasonable expectation partly fed by popular culture where there is always a satellite overhead," says Mr Richelson.

"In reality, no matter how much you collect you are only watching and listening to a small part of the total environment."