This is a much longer running issue than the Obama administration.

Market distortions favoring heavy trucks include:

* The Corporate Average Fuel Economy (CAFE), enacted in Congress in 1975 under the Ford administration in reaction to the Arab oil embargo, with its tiered structure on passenger vehicles vs. trucks.

* The "Chicken Tax", tariffs on light trucks enacted by Lyndon Johnson as a reaction to French / West German tariffs on chickens. While much of this trade war was repealed, the light truck tariff never was.

* Section 179 tax deductions, which are biased in favor of heavy vehicles. As I understand it, this particular deduction was inserted into the tax code via the Deficit Reduction Act of 1984 under Reagan, for the purpose of aiding small businesses that might rely on such.

So it's been, from my perspective, a fairly non-partisan desire from all of US politics, with protectionism as perhaps part of the goal, but perhaps due to other goals that had unintended effects.

Personally, I think that government regulations can only explain so much. Even with the market distortions, trucks tend to be rather expensive compared to smaller vehicles sedans, and that's before factoring in the bad gas mileage. My presumption is that America's vastly more rural landscape contributes just as much to the preference for trucks as government policy.

I do surmise from articles, though, that the above US policies have impacted the ability for lighter pickup trucks to entering the market. I suspect that some smaller pickups, like the small "kei trucks" that seem to have a bit of a following in the US even with all the regulatory hassle, would be much more present if a lot of these protections were removed.