In her book Troll Nation, Amanda Marcotte argues that owning the libs is so central to the political right that any effort to show care and concern for the well-being of others, or even for oneself, is viewed as suspiciously liberal. She gives the example of rolling coal, the practice of illegally modifying a diesel pickup truck to produce clouds of black smoke.^[22][23] Exhaust from rolling coal is sometimes directed at drivers of fuel-efficient cars and cyclists, in order to offend their presumed liberal environmentalist values. Marcotte argues that rolling coal has no value outside of trolling liberals. It costs the coal-roller money, increases fuel consumption, can void the warranty of their vehicle, and may violate air-pollution laws. Hence, Marcotte argues, rolling coal is an expensive and counterproductive way to misconstrue environmentalism as an identity marker instead of a policy matter