Until at least 2009, there was a great deal of "offshoring" of U.S. jobs in tradable sectors, companies shifting domestic production to other countries, both for their own production and for their inputs purchases. Use one of the trade models to explain this. What changes might have led to the increase in offshoring? (The changes may be "exogenous" to the model, off course.) At least 3 of the models we looked at offer an explanation, and these differ a lot. Just pick one of them.