Really? Well, I will agree that it won't strictly be our military actions that deter more terrorist attacks on this country; but it is clear that they have greatly contributed to that goal.
And if it's as easy as you claim, it would have been done by now. Al Qaida has made it a priority to repeat attacks on this country ever since 9/11, but to date they have failed to do so. Why? Because the US military has fractured that organization across the globe to the point that their only effectiveness is in spewing their propaganda in a dire attempt to get recruit disenfranchised young male Muslims. They have had limited success with that in other countries but not here.
Trust me, as a security specialist who has access to high levels of government information sources, I have a pretty good idea of the "threat" and what is being done to counter it. I am also pretty well versed in the vulnerabilities in this country and what countermeasures are being employed to reduce the risk. So while it's a lot of fun to speculate as to how successful US foreign policy has or has not been, the bottom line is that the efforts under the Bush administration have done an effective job of keeping the battle overseas (to the point that Obama is continuing them, despite claims to the contrary) and a major change would be very detrimental to our security. It will cost us even more in the long run, not only in dollars but also lives.
