When Ron Paul talked about blow back being involved in the 9-11 attacks, people twisted his words to try to make it seem as though he claimed we invited the attacks. What he meant was that al qaeda used our presence in Saudi Arabia as a recruiting tool. To muslims the presence of a non muslim army on Arab soil is a sacrilidge. It doesn't matter if we have a justification to be there or not or if we are being peaceful or not. They will use it for recruitment. Ron Paul was right to say we wouldn't want an occupying army on our soil either and such a thing could stir resentment and rebellion, but we wouldn't see it as an attack on our religion as long as they were acting peacefully. They do. A non muslim army on muslim soil is seen as a sacrilidge to their faith. Unfortunatly now Iraq is even more religious than it was under Sadam and any kind of aggressive behavior is used for recruitment even if the aggression is being used to secure the peace. They think in religious terms which the Japanese and Germans didn't when we occupied them for the purpose of rebuilding. We should have evaluated that before going in.
We told the Saudis we would leave Arabia after the Gulf War ended. We stayed ten more years which built up resentment among fanatical extremists. Does that mean we invited the attacks. No. It means extremists used this as a recruiting tool to fulfill their goals. Also what isn't a secret is that the CIA was involved in training Bin Ladin. Now if that's not blow back what is?