Rules for regulatory intervention aim to ensure that cumulative impacts remain or fall below thresholds of acceptable cumulative harm. A rule has two key dimensions: (1) its strategy – how it changes cumulative harm by reducing impacts, offsetting impacts, restoring, or facilitating coping with impacts; and (2) its approach – how it influences actions that cause impacts by using mandates (sticks), incentives (carrots) or information and persuasion (sermons) to influence adverse actions, or by using direct state action (state rescue). Each strategy and approach has strengths and weaknesses in addressing cumulative harms, and a cumulative environmental problem will likely need a carefully designed mix. In designing this mix, important challenges are ensuring connected decision-making so that actions are not considered in isolation; ensuring comprehensiveness, to avoid overlooking actions, including "de minimis" actions that could cause cumulatively significant impacts; managing costs related to intervention; and adapting interventions to accommodate changes to impacts and new information. Real-world examples illustrate legal mechanisms that include features designed to address these challenges.