Protectionism becomes more likely during economic downturns, and Emmanuel notes that public support is headed that way:
The most recent Pew Global Attitudes survey found that, in a sample of twenty-four countries, the United States came dead last in terms of viewing trade favourably… “Support for international trade continues to decline in the United States – 53% of Americans say trade is good for their country, down from 59% last year and 78% in 2002. Support for trade is lower in the U.S. than in any other country included in the survey.”
Trade Diversion 