How effective was this at anything other than making loopholes big enough to drive a truck through, and eventually getting assembly moved to NAFTA countries?

Having a 40 mpg target for a small truck and a 25 mpg target for a big truck makes it pretty hard to build and sell a small truck.

Hmm, that's interesting. If manufacturers have been basically locked out of making small pickup trucks due to unattainable fuel efficiency requirements [1, 2], an implication of that is that as EVs become easier to make at reasonable cost, there's a potentially huge untapped market that could be filled by whoever is the first company to make a small, simple, and cheap electric pickup truck.

A modern version of, say, a Datsun 620 [3] or an 80's Ford Ranger [4] could be pretty popular. One might even be able to circumvent the chicken tax by importing the body/frame of a foreign-made truck and building an electric drive train in the U.S. or NAFTA country.

[1] https://en.wikipedia.org/wiki/Corporate_average_fuel_economy...

[2] https://en.wikipedia.org/wiki/Corporate_average_fuel_economy...

[3] https://en.wikipedia.org/wiki/Datsun_Truck#/media/File:Datsu...

[4] https://en.wikipedia.org/wiki/Ford_Ranger#/media/File:1st-Fo...

> there's a potentially huge untapped market that could be filled by whoever is the first company to make a small, simple, and cheap electric pickup truck.

Well, the third really; Ford made 1500 1998-2001 Ford Ranger EVs, and Chevrolet made a few hundred 1997-1998 S10 EVs. But yeah, one with modern batteries and drive trains and (therefore) decent capacity and range could sell a bunch.