What childish rubbish. Being nationalistic, with no armed forces outside of their own country, didn't stop the terrorists from bombing Saudi Arabia 3 times in the last two years.
It didn't stop them from bombing a French oil tanker. It didn't stop them from bombing a nightclub in Bali, hardly a world policeman. It didn't stop them from waging a full scale offensive war first in Bosnia and later in Kosovo...much less in Chechnya. It didn't stop them from murdering Israeli olympic atheletes in Much in 1972, either.
And they've attacked us in 1982 in Beirut, in 1993 at the World Trade Center, in 1998 at two different African embassies, hitting the USS Cole in 2000, our WTC's and Pentagon in 2001, etc.
You can spout your ridiculous, jingoistic, sophomoric, moronic pabulum about withdrawing into "fortress America" all day long, but no rational adult is going to be duped by such perverted madness.
For one thing, it isn't physically possible to defend 100% of every piece of American property and 100% of all American lives 100% of the time.
On the other hand, it is *imminently* possible to wipe out entire continents with a global nuclear, chemical, and biological offensive.
So the solution resides closer to all-out offense, which is mathematically *possible*, rather than to your pathetic concept of eternal infinite defense, which won't even work on paper.