Let's see the results of a poll that asks if people would be willing to take climate action that doubled the price of airline tickets, or that doubled the price of most fruits and vegetables in the supermarket. I would expect a very different result, yet this is what is necessary to offset the emissions in air travel and international shipping. (I pulled this "double" number out of a hat, but it seems to me to be far less ridiculous than your assumption that action on climate change won't affect prices.)
It's the same issue with domestic manufacturing. Of course all Americans want their products to be manufactured in America. But virtually no Americans are willing to pay a higher price for them. Stores long ago stopped bothering to stock American made products next to their cheaper foreign counterparts because no one bought them. What people say they want is irrelevant; what matters is what they actually buy.
> In the abstract I see no reason that global trade should breakdown if a significant majority of people in the world can agree about labor standards, human rights standards, etc.
If a majority of the world agreed on labor standards and excluded the rest from trade, there would be no need for protectionism. Manufacturing would be a level playing field so Americans could compete directly with foreign companies on price. Unfortunately this isn't the world today. It's not possible to compete in manufacturing with countries where laborers are paid under a dollar an hour, so as long as we have free trade with such countries our manufacturing will never be able to compete.