First of all, there are limited ways in which you can really train in a manner that would guarantee attracting attention for some of these attacks. Suicide attacks (such as 9/11) really cannot be practiced in real situations since they end in death. Thus, the first time they are done is the last time they are done. It's not like we had that many terror attacks in the US and that they simply shifted to Iraq (fight them over there and all that bullshit). No, the invasion actually led to more attacks over there, not necessarily less here. Secondly, your "no real safe haven" argument is unfounded. There is no way for the US to patrol all of the mountains, caves and other areas in either Iraq or Afghanistan (are those even the only places to hide?). In addition, the terror attacks that we have seen here require little or no traditional combat training in the sense of firearm use (they use bombs or improvise and turn planes into weapons).