I don't think it's much of a leap to take Ron Paul's idea of non-interventionist: "Bring all of our troops home," and expand it to what the effect would be: isolationism.
Sure, it might not start out as a statement that we don't want to continue this trading relationship. However, reducing our global reach is a very bad idea, in my opinion. Reducing our reach means that we won't have the bases for possibly expanding into other areas when the stuff hits the fan.
Probably, anyone who advocates such an idea just doesn't know what it is that we do in the world.
There is a reason that the founding fathers gave the power to build the armed forces to the congress. These United States have not always existed without enemies who would wish to do us harm.
Arguably, there are people today who wish to do us harm.
Some people may not see this. At present, in addition to being a debtor nation, we also are the largest consumer nation. Other countries depend on our consumption to finance their lifestyle/growing economy/relative opulence.
If the economic conditions of this country really start heading downhill on rollerskates, then other countries will probably also feel the belt tightening.
I doubt that the economy will decline severely.
Trade is important, but so too is security. Part of the reason that many people left Baghdad was because they did not feel secure. Maybe people are now starting to return because the security situation has improved.