I should also say that as someone who thinks NAFTA was a smart policy and an important-though-oversold policy achievement of Bill Clinton's administration, I find it kind of painful to watch. Hillary Clinton's husband's administration had a perfectly defensible record on trade policy and that is why she defended it in the past -- she ought to keep defending it now. Instead, we get these weird contortions from her and Obama pressing a very dubious line of attack that Clinton won't challenge on the merits.
Save your eyes. Take breaks.