Several years ago economist Bryan Caplan provided the most succinct and helpful statement about how we should think about free trade: “We’d be better off if other countries gave us stuff for free. Isn’t ‘really cheap’ the next-best thing?”
As with any simplification, critics could find many reasons to grumble about what that leaves unstated (e.g., trade leads to offshoring of jobs). But it highlights an important point about why free trade matters. Free trade is about as close to a “free stuff” economy as you can get in the real world.
A primary effect of free trade, as Tim Fernholz says, is that when companies hire or set up factories abroad to take advantage of cheap labor elsewhere, Americans’ real income goes up because a lot of the stuff they’re buying is cheaper.