This is not some back-bencher, but the leading counter-terrorism adviser:

President Obama’s top counterterrorism adviser called it “inconceivable” that Pakistan was not providing a “support system” for Osama bin Laden, who was killed Sunday in a raid in a mansion north of the capital city of Islamabad.

“We are pursuing all leads on this issue,” Deputy National Security Adviser John Brennan said during a White House briefing. “I think people are raising a number of questions, and understandably so.”

This mirrors similar questions from Sen. Carl Levin (D-MI) earlier today.

That’s extremely candid on Brennan’s part, but what else could he say? It makes no sense, given the facts that we know, that Pakistan was completely in the dark. Brennan didn’t speculate on what help bin Laden had inside Pakistan, leaving that open to the imagination. There’s no shortage of options, from the military to the ISI intelligence service. We don’t know who was playing the double game but the suspicions are obvious.

But it also doesn’t make sense, given the facts that we know, that Pakistan was similarly in the dark about the US mission. This very smart essay from a former DIA analyst explains:

Secondly, his compound could not have been attacked from Afghanistan, him killed and his body taken by US Navy SEALs flying US helicopters so close to Islamabad without official Pakistani government cooperation. The US insisted Pakistan played no part in the operation and that the team flew from Afghanistan. That clearly is a cover story for Pakistani public consumption to try to avert overwhelming anti-Pakistan and anti-US demonstrations, which are probably inevitable in any event.

Abottabad is not some remote village on the border. It is a large town in eastern Pakistan, on the main road to Kargil and the north as well as to Muzaffarabad and Pakistani Kashmir to the east. It is northeast – towards India – of Islamabad and within the Pakistan air defense intercept zone for the national capital which is protected by the Pakistani integrated air defense system. Nothing can fly in that region without detection and without permission from the Pakistan Air Force, even from Afghanistan.

The conclusion here is that some kind of deal was made. Either the US found out about bin Laden’s location and Pakistani complicity and forced the government to allow a raid, or Pakistan came to the US and gave up bin Laden for something undisclosed in exchanged. Given what we know about the al-Libi intelligence, I think it’s probably the former. But that doesn’t mean that Pakistan didn’t drive a bargain. It’s impossible to know whether Raymond Davis, or control over drone attacks, was part of the deal. That won’t be clear for some time.

Brennan certainly stuck with the cover story that Pakistan is an able partner in counter-terrorism efforts, if a complicated and conflicted one. And there’s a spillover effect if they get too out in front and accusatory of Pakistan, that the country’s political leadership could fall. But I think everyone can conclude that this is a cover story, meant to obscure the very difficult deal that was reached between the two countries.

The other nugget of information from Brennan was that Osama bin Laden himself used his wife as a human shield during the mission. That’s a pretty humiliating way to go out, and I think it lends credence to the fact that there was no way he would willingly leave that compound alive.

…The power went out in Abbottabad two hours before the raid, and returned 15 minutes after. This mission clearly had Pakistani foreknowledge.