Over the past decade, the Koch Brothers have become a major political force, funneling money from their family company into organizations that support conservative politicians and causes--including the denial of climate change.

So Charles and David Koch wouldn't seem like enthusiastic supporters of electric-car maker Tesla Motors.

Yet the Koch-funded group Americans for Prosperity is one of 10 signatories on a letter sent to U.S. governors and legislators urging them to support Tesla's direct-sales business model.