Painful as it may be, it’s valuable in the wake of any tragedy to dissect what happened with the goal of preventing a recurrence.

September 11 wasn’t just any tragedy. Dissecting it, however depressing, is still the goal of The Looming Tower, a 10-part series that starts rolling out Wednesday on the streaming service Hulu.

Jeff Daniels (top) gives another superb performance as John O’Neill, a real-life FBI counterterrorism bureau chief who had been convinced for several years that Al Qaeda was planning a major attack on American soil.

O’Neill put together most of the pieces from a complex puzzle. He never finished it, partly because he was never able to pry potentially critical information out of the counterterrorism chief of the CIA, Martin Schmidt (Peter Sarsgaard, right).

The Looming Tower focuses on O’Neill’s quest and frustration. The real-life 9/11 Commission report issued several years later came down hard on the failure of agencies to share information, a conclusion that was widely taken to vindicate O’Neill and his concerned colleague Richard Clarke (Michael Stuhlbarg).

Yet showrunner Dan Futterman doesn’t paint a black and white picture here. Schmidt, a composite of several real-life CIA officials, sidesteps his obligation to share intelligence not purely out of territorial instinct, but because he fears the FBI would barge in and start arresting people the CIA feels it’s vital to continue observing.

CIA analyst Diane Priest (Wrenn Schmidt) likewise feels it would be more dangerous to give the FBI certain intelligence than to withhold it. 

On the other side, O’Neill is no white knight. He’s profane and obnoxious, and his personal life is a train wreck wherein he’s juggling an ex-wife and family alongside several women who think they’re his one and only.

We wouldn’t care if O’Neill were juggling the entire faculty of Georgetown University, of course, if he were simultaneously stopping mass murderers – and Daniels makes it clear that’s the real driving force in his life.

Toward that end, he grooms and supports Ali Soufan (Tahar Rahim), a young Muslim who became an FBI agent essentially on a dare.

Soufan soon becomes O’Neill’s most effective weapon, because he can work inside the Muslim culture. He’s happy to do this because the more he learns about Al Qaeda and radical Islamic groups, the more it angers him that in his mind they have perverted his peaceful religion.

Much of The Looming Tower focuses on Soufan (left), both personally and as an agent who has to learn the game at warp speed.

Meanwhile, Futterman methodically shows how the 9/11 attacks were seeded and planned.

Toward that end, The Looming Tower incorporates real-life video from, among other things, an interview Al Qaeda leader Osama Bin Laden gave to ABC News.

We see the pattern of attacks O’Neill took as evidence something major was looming, through bombings of U.S. embassies and the 2000 attack on the USS Cole.

We also see the towers, two buildings that to most Americans were tall and plain, but to another group had become a symbol of the power and evil of the West.

The Looming Tower doesn’t conclusively prove O’Neill and Clarke could have helped stop the attacks if they had all the pieces of the puzzle. It makes a good case that the odds would have gone up.

More than 16 years later, The Looming Tower also suggests, there’s plenty we need to remember and learn from both them and us.