Why Do They Hate NAFTA?

The Democratic candidates did a lot of vote trolling Tuesday night at the expense of two of our biggest commercial allies. A point made in this clip by Tim Russert.



The point here is Canada and Mexico are two of the three biggest trading partners with the US ... (2006 US Census figures)
Canada: $533.67
China: $343.00
Mexico: $332.43
Japan: $207.74

Question: Why do Democrats spend so much time pandering to enemies and yet at the same time taking whacks at our allies. Investors Business Daily:

Far from being an enemy, Mexico is a partner with whom we did $350 billion in two-way trade last year. In the process, we've gained millions of high-paid jobs in the U.S. The relationship has boosted U.S. incomes an average $2,000 per family since 1994. Besides buying 35% of our global exports, Mexico and Canada are also two of our biggest oil suppliers, selling us energy we'd be in huge trouble without.
Casting NAFTA nations as villains sends a chilling message to the dozen other nations that have since signed NAFTA-like agreements — countries as friendly and diverse as Singapore, Jordan, El Salvador, Australia, Morocco and Chile