Many cleantech jobs already are overseas. Other countries are zooming ahead of the US in renewable energy technology and products.
The primary reason the United States led in aerospace, communications technology, information technology, computing and the major new energy technologies of the later 20th century (gas turbines, nuclear, wind and solar power) is because the U.S. government made a series of smart investments on the cutting edge of each of these technology fields to catalyze entrepreneurship and innovation.
However, such public investments are sorely lacking now as is a coherent national policy on clean energy. Seems like we spend far too much time squabbling with each other instead.