Abstract: This Article argues that the pending feuds between neighboring states over marijuana decriminalization demonstrate the need for a strict doctrine limiting a state’s regulatory authority to its own borders. Precedent recognizes that the dormant Commerce Clause (“DCC”) “precludes the application of a state statute to commerce that takes place wholly outside the State’s borders, whether or not the commerce has effects within the State.” This prohibition protects “the autonomy of the individual States within their respective spheres” by dictating that “[n]o state has the authority to tell other polities what laws they must enact or how affairs must be conducted.” But this principle was called into doubt in July 2015 by the U.S. Court of Appeals for the Tenth Circuit in an opinion by Judge (now Justice) Neil Gorsuch, which concluded that this “most dormant doctrine in [DCC] jurisprudence” had withered and died from nonuse. The Tenth Circuit’s conclusion, which approved Colorado’s purported direct regulation of coal-fired power generation in Nebraska, ironically coincided with Nebraska’s attempt to enjoin Colorado’s pot-friendly laws. Nebraska contends that Colorado’s commercial pot market allows marijuana to “flow . . . into [Nebraska], undermining [its] own marijuana ban, draining [its] treasur[y], and placing stress on [its] criminal justice system.” While Colorado celebrated its newfound power to impose its legislative judgments on Nebraskans, the festivities might be short-lived. Colorado failed to recognize the impact the extraterritorial doctrine’s apparent demise may have on its own marijuana-legalization experiment. If Colorado is empowered to regulate coal burning in Nebraska because of its effects in Colorado, what prevents Nebraska from projecting its own laws across the border to regulate Colorado marijuana transactions that affect a substantial number of Nebraskans?