Fossil fuel companies and others have spent decades casting doubt on climate science to allow them to continue to profit. As documented by climate communication expert John Cook and others, these strategies have taken many forms: deny, dismiss, delay, deflect; and they have evolved over time. They’ve also included a concerted effort to recast political speech, banned and regulated in some contexts, as protected free speech, giving corporations more leeway in broadcasting their messages. In a special collaboration with Climate One, we trace the origins of this free speech argument and break down the tactics used to spread misinformation.