The future of the North American Free Trade agreement depends in the political will of three different countries. It is unlikely that the trilateral agreement will disappear entirely under any circumstances, but whether it expands or contracts and is liberalized or undermined depends on factors including the pace of economic recovery and attitudes towards it.
Of the three countries, Canada suffered least from the global recession, but has ongoing issues concerning softwood lumber, U.S. reluctance to support a pipeline from the oil sands to Texas, the unilateral way in which Homeland security is being imposed in matters affecting Canada, and some of the protectionism of the stimulus packages in which Canadian companies were not allowed to bid. Thus Canada may negotiate from a position of strength for more concessions from the US.
The US in turn is moving increasingly towards protectionism, which may affect many NAFTA issues. Environmentalists and the 99% tend top oppose NAFTA, whereas big businesses favour it.
Mexico is worried about failing US drug policies that have turned many Mexican cities into war zones and may ask for changes in NAFTA. US attitudes to immigration from Mexico and crackdowns on illegal immigration have also been deeply unpopular in Mexico.