While this isn't the best way to address the issue, the US is way too dependent on gasoline/diesel for transportation. It's not sustainable.
He had that big falling out with Elon so that he can't be accused of pandering to him when electric car sales go through the roof.
I have also heard that this is really "big oil's" plan, they always manage to cause a huge price spike just when green energy is about to take over the market, somehow this stops the green revolution and forces everyone to go back to using fossil fuels.