middle class. And their trade is governed by 'trade deals' to a much greater extent than ours is.
Trade is 51% of Canada's economy. Guess which has a stronger middle class. The same is true of Sweden (62%); France (42%); the UK (64%); Australia (33%). If there is a link between the strength of a country's middle class and the degree to which its economy engages in foreign trade, I think you would have to conclude that it is a positive correlation.
Of course the strength of any country's middle class depends primarily on its progressive taxes, strong safety net, support for strong unions, effective corporate regulation, etc. It is worthy of note, however, that the progressive countries that do a much better job of these than we do in the US also choose to trade with other countries a whole lot more than the US does. They obviously believe that trade (and yes, trade deals) enhances these progressive policies and does not negate them.
Obviously we should support GOOD trade deals, just as we should support GOOD peace treaties, GOOD climate change agreements, GOOD arms control agreements, etc. Liberals, in general, are much more supportive of peace agreements, climate change agreements and basically any kind of international agreement, but we want GOOD ones rather than just any agreement.
Conservatives, OTOH, generally oppose international agreements since they, by definition, restrict a country's freedom of action thus impairing its 'national sovereignty'. It is little surprise that their base wants out of the UN, the WTO and international agreements of all kinds.