Slate's theories on why 9/11 hasn't recurred in the US

This morning I noticed this nice compilation by The Null Device, of Slate articles on the threat of terrorism:

Slate has a series of articles examining various theories on why there hasn't (yet) been another 9/11-style attack on the US. The theories are:

• The terrorists-are-dumb theory (i.e., they just got lucky)
• The Near-Enemy Theory (i.e., they're too busy in Pakistan/Afghanistan)
• The Melting-Pot Theory (i.e., American Muslims are too well integrated to sympathise with al-Qaeda)
• the Burden-Of-Success Theory (i.e., 9/11 has set expectations that are hard to meet)
• The Flypaper Theory (i.e., why kill Americans in the US when you can kill them in Iraq?)
• The Bush-Kept-Us-Safe Theory (i.e., invading Iraq and abducting and torturing random Muslims actually worked)
• The Electoral-Cycles Theory (i.e., they're timing their attacks to influence elections)
• The Time-Space Theory (i.e., al-Qaeda is just biding its time, just you wait...)

Very interesting, albeit rather worrying.

Decided I also need to read up on the RAND Corporation...