One-liner: A framework for intelligence analysts to use to think systematically about the potential for the rise of a peer competitor to the United States. The potential emergence of a peer competitor is probably the most important long-term planning challenge for the Department of Defense. This report addresses the issue by developing a conceptual framework of how a proto-peer (meaning a state that is not yet a peer but has the potential to become one) might interact with the hegemon (the dominant global power). The central aspect of the framework is an interaction between the main strategies for power aggregation available to the proto-peer and the main strategies for countering the rise of a peer available to the hegemon. Then, using exploratory modeling techniques, the pathways of the various proto-peer and hegemon interactions are modeled to identify the specific patterns and combinations of actions that might lead to rivalries. The dominant power has an array of options available to limit the growth of its rivals or to change their ultimate intentions. Too confrontational a strategy, however, risks making a potential neutral power into a foe, while too conciliatory a stance may speed the growth of a competitor. Exploratory modeling suggests which attributes of the countries are most important and the sensitivity of the dominant power to perception errors.