We know that Khalid Sheikh Mohammed was the mastermind behind the first attack on the towers and that he was behind 9/11. If he was the mastermind of their U.S. operations, then it’s no wonder we haven’t been attacked again.

Khalid Sheikh Mohammed’s capture four years ago didn’t shut down al-Qaida or bring the Americans to Osama bin Laden. But if his mega-confession is to be believed, his arrest was a crushing blow to bin Laden’s plans for even more deadly attacks in the wake of 9/11.
His expertise was never replaced and his absence has contributed to the group’s transition from a fear-inspiring attack force to a hate-filled voice on the Internet, urging others to wage terror against the West.
“In terms of competence for managing, planning and executing terrorist attacks, KSM was the best in al-Qaida,” said Rohan Gunaratna, a terrorism expert and author of a book on al-Qaida. “That’s why Osama bin Laden and other important al-Qaida leaders entrusted him with so many operations.”
[…]
He was the mastermind of the 9/11 jetliner attacks and, in their wake, certified his bloodthirst by personally beheading Wall Street Journal reporter Daniel Pearl – bragging about it on the Internet then and in the testimony transcript of last Saturday.
“I decapitated with my blessed right hand the head of the American Jew, Daniel Pearl, in the city of Karachi, Pakistan,” he said. “For those who would like to confirm, there are pictures of me on the Internet holding his head.”
His operations ranged from his admitted involvement in the 1993 attack on the World Trade Center, as well as a failed scheme known as Bojinka to bring down 12 Western airliners in Asia – claims that are well documented.
[…]
He “sang” to interrogators almost from the start, after his March 2003 arrest at a house outside the Pakistani capital. Much of the information in the 26 pages of released testimony has been long known.
But even if his self-proclaimed status is somewhat exaggerated, he “gave the Americans lots of information about what kind of ideas al-Qaida had, and how they put their plots together,” said Magnus Ranstorp, a terrorism expert at the Swedish National Defense College.
“Mohammed’s information gives us a glimpse into the group’s imagination. On an operational level, I don’t think they have ever been able to replace his experience,” he said.
Experts agree the arrest was a major setback for bin Laden’s terror network, and one from which the group has never quite recovered.
[…]
Many of the world’s recent terror attacks – such as the March 11, 2004 train bombings in Madrid and the July 2005 attacks in London, were carried out by local groups with no proven links to bin Laden’s inner circle. Although undoubtedly inspired by bin Laden’s call for global jihad, al-Qaida no longer could lend the kind of direct support it offered the 9/11 hijackers.
“The role of al-Qaida has changed a lot,” said Talat Masood, a former Pakistani general and security analyst. “It has become devolved and amorphous. It’s a more ideological and inspirational force and does not have a centralized command anymore.”

Read the rest here.
Hopefully his expertise has not been replaced.