The USA isnt besieged because we are the bastion of all good and morality. We are besieged because we are prosperous. We are besieged because we are successful. We are besieged because we believe in freedom and equality. We are besieged because we are a western power founded upon Judeo-Christian beliefs. Lastly, we are besieged because we exist.
It is an us vs. them conflict because there is nothing we can do to make them stop. Only they can stop themselves. Nothing we do will make that happen. Only an enlightenment of their own creating will do so. There have been some notable success' of that, but unfortunately they still get crushed by the other side.
What? You think that every single terrorist has been that way from birth and that we had no influence or way of changing their terrorist-nest? Many of the terrorists don't like America for many reasons. You correctly pointed out that one is existing hatred from within the Muslim world. After all, if your family, friends, and everyone around you hated or at best disliked something, you would hate it too. But there's another facet,as weel, in that some potential terrorists are swayed by diehard radical current terrorists who find real or fictional evidence to prove America is evil. Put yourself in their shoes. We've been total assholes to Muslims since Islam left the Middle East. Frequently, during the Middle Ages, Muslims would be at best, outlawed from many professions, property ownership, and public prayer. They were outcasts (Note: Christians in Islam areas weren't treated much better.) At worst, in some places, such as Spain and Turkey, Muslims were persecuted, tortured, and executed. After WWII, the US dominated Allies basically said "Fuck you" to Palestine. In recent times, the US also attacked Iraq twice and Afghanistan. The US gives the most foreign aid to Israel, generally the most hared country by Muslims.
To the Muslim world, the Western world and the US especially look very anti-Islam. They view the US as a bunch of carpetbaggers who have only made things worse since they showed up. The terrorists try and convince young people that the western world and the US especially need to be destroyed ASAP for the good of the their country, Islam, the world, or whatever. Most Muslims reject this notion; however, the more ammo we feed these people, the more people they'll convince to join. Each bad thing the US does or did may just be the thing to convince a person to go terrorist. So yes, the US can in fact sway terrorism. I do agree that convincing current terrorists that what they're doing is stupid is in and of itself stupid, but that doesn't mean that, given the oppurtunity, we shouldn't make a reasonable effort at changing their views. That is, after all, the whole point of jail.
Your statement that there's nothing we can do to stop terrorists is absurd. If the US can convince terrorist-filled countries like Pakistan or Iran to step up their anti-terrorist programs without invading the country, hasn't it helped stop terrorism? There is a middle ground between "Kill 'em all!" and "Ignore them", which, by your opinion, you seem to think nonexistant. If we could seperate terrorists from their supplies, they're no longer a threat. If we could seperate them from each other, we could drastically reduce their likelihood of performing an attack. If we can seperate them from the general public, we've cut off the source of new terrorists. If we could cut them off from America, they're not a threat. The last one is obvoisly impossible, but you get the idea.
On another note, this isn't aimed at you or anyone in particular, but several comments that have been made are dangerously "Christian world vs. Muslim world" which is obviously false. There are two conflicts: UN vs several countries (Iran, Pakistan, North Korea, Sudan, and others) and US government vs anti-US violent terrorists. If you get the groups wrong you might broaden them to places and people who aren't involved. It's not US government vs Muslims or UN vs Islamic countries. Remember, most Muslims are NOT terrorists. Juat wanted to make sure everybody keeps this striaght.