Earlier this month, standing on the White House driveway, President Donald Trump hawked a fleet of gleaming Teslas with the kind of gusto normally reserved for his campaign rallies. Clutching handwritten notes about prices and models, he said, "I'm going to buy one because it's a great product, as good as it gets." Elon Musk, Tesla's CEO and a key figure in the administration, stood nearby.Many assumed Musk's proximity to Trump would be a net positive. But his involvement with the Department of Government E ...