Unfortunately most economists don't have a very good grasp of arithmetic. The NYT found one of those numerically challenged economists who told readers: "Only an outbreak of protectionist policies or a sharp rise in international shipping costs could slow or temporarily reverse manufacturing’s declining share of employment in the United States." Actually, unless someone believes that the United States can run large trade deficits forever, and in effect foreigners will always give us more money for nothing, it is almost inconceivable that manufacturing will not grow as a share of GDP in future years. It's just arithmetic.
--Dean Baker