Even though the United States has achieved the long-sought goal of energy self-sufficiency, energy security remains a strategic and economic challenge. Despite “self–sufficiency,” the U.S. still imports significant quantities of oil and natural gas, as well as solar panels and wind turbine components, and prices for all of these products reflect global market dynamics. Traditional concerns about global supply disruptions remain, and new risks have also emerged. Domestic energy availability can be impacted by storms, terrorism, and cyber threats. Moreover, the rapid growth of renewable energy (and batteries) may help mitigate conventional concerns about fossil fuels but may also reveal new risks. The U.S. and its allies have a cooperative system for dealing with oil supply disruptions, including a large domestic strategic crude oil stockpile, but there is no similar domestic or international framework for dealing with other, emerging risks. The U.S. can aid the transition to a lower-carbon energy system by providing assurance that risks associated with that transition can be understood and managed, both at home and by working cooperatively with allies (as has long been the case for oil security).