First off, Bin Laden did not even plan the attack, it was presented to him by it's chief architect, a Kalid Sheik Mohammed (captured by the US in Pakistan in 2002), he would have known of
OBL's call for Jihad against the US in 1997, so he knew that his 'planes operation' would get attention, funding and what resources
AQ had at their disposal, in late 1999, it did, from
OBL personally, in what would have been a very rare intervention from
OBL in the fragmented world of international Islamic terror.
Originally intended to comprise of 10-12 aircraft, striking targets almost simultaneously, WTC, Pentagon, White House, Capitol Hill, FBI and
CIA H.Q's, Camp David and maybe a nuclear plant or two.
But the limiting factor was not US airline security, it was US Immigration, despite their mistakes that allowed people in with too little scrunity, including known
AQ suspects, they did refuse enough people to cause the scope of the attack to be scaled right down, also the much vaunted training Afghanistan training camps run by
OBL, provided very little in the way of terrorists that could even live in the West without too much difficulty or suspicion, much less enroll in flight training classes.
For most of the 1000's who went through the camps were training for Islamic inspired campaigns in places like Bosnia, Kashmir or the Chechen wars, most had no interest or inclination in becoming international terrorists, they were training for conflicts in their own backyard.
One of
OBL's propaganda videos is of him with a large cadre of trained up terrorists, is a deception, the 'terrorists' were just local Afghan fighters,
OBL told them to wear the masks and other symbols of extreme Islamic terror, but they'd have to bring their own
AK-47s for the filming, for which they would be paid for!
So in a sense of suitable personnel, Kalid Sheik Mohammed's plan, facilitated by
AQ/
OBL, did shoot it's bolt.
Why do the attack on the US, why proclaim Jihad against the USA in the first place?
Because from the late 1980's
OBL had come to be influenced by someone by who would become his no.2, his spiritual mentor, an Egyptian doctor, al-Zawahiri.
He had some history, one of the plotters in the Sadat killing in 1981, jailed for years, then released, he had a doctrine of terror attacks to overthrow Western backed regimes in the Muslim world, like his own nation, to allow a revolutionary Islamic government to take over, for keeps.
Killing Sadat did not provide the general uprising that he was banking on, so he eventually gravitated to Afghanistan, where he and others like
OBL, convinced themselves that they had not just evicted the US
SR from Afghanistan, but caused that superpower's collapse.
Nonsense of course, the US
SR went because at some point, the breakdown in the economic and other aspects of life within the Communist command economy, was going to happen, whatever happened in it's foreign wars.
Gorbarchev could not really undue all those decades of stagnation.
Undaunted, the Egyptian planned his follow up, when an Islamic party looked like winning an election in Algeria in 1991, the army stepped in, cancelled the ballot and repressed the Islamists.
So in response, helped by
OBL and his new deputy in Sudan, a insanely vicious terror campaign was waged in Algeria, with a gloves off response from the military.
Now the Egyptian had a new idea, carry out attacks of such indiscriminate slaughter against the civil population, that in time the people would rise up and demand a 'true' Islamic government.
Just like in Egypt a decade before, it did not happen, in fact despite the repressive military government, almost all public opinion was against the Islamists.
Then the various Algerian Islamist terror groups fought agmonst themselves, each accusing the other of straying from the true path.
Out of this came a last message from one of the groups, that reflected an extreme strand of the thinking now forming in
OBL and his deputies mind.
Since the people have not risen up, they must be so polluted by Western influence, that the only way to pure Islam in Algeria is for the entire population to be killed, except the few members of the group spouting this stuff.
Kicked out of Sudan, now in Afghanistan,
OBL's disparate group faced defeat, all across the Islamic world, Egypt was still under an 'impure' government, so was Algeria, so was the whole Gulf region, even those that were not pro Western, like Syria or Iraq, cracked down hard on any hard line Islamic movements, they were after all a threat to the Ba'th ascendancy in those two states.
The Muslim people, despite their many privations, despite US support for Israel, despite corrupt leaders bleeding countries dry from their palaces, had not risen up to overthrow these leaders and cast impure Western influences out.
So, they themselves were corrupted by these Western influences, how to stop,
this? Or just roll it back enough to help the Islamist cause?
Well, who was the biggest provider of Western influence?
The USA, from arms supplies to Hollywood and rest of their vast media and range of other commercial products.
To help this re-awaking of pure Islam, who was the most unpopular Western nation in the Islamic world?
The USA ironically, almost entirely due to their massive and solid support for Israel.
Could a huge mass casualty strike upon the USA, cause them to pull out both militarily and largely commercially too, from the Islamic world?
Maybe, or maybe not, but would a furious US unleash an ill targeted and vengeful response on Muslims generally, thus massively extending the very limited support of people like
OBL?
OBL was convinced by the Egyptian that this course of action was the only way forward, hence the 'Jihad' against the US being declared, the African Embassy bombings, but a really big hit was needed, so when an ambitious Islamist came asking for help for his 'planes operation' against the US,
OBL was all ears.