Because the earliest years of life are a period of incredible growth, they present an opportunity to shape strong and positive development. Good health, secure and stable families, and positive early learning environments are necessary to foster children's physical, intellectual, and social-emotional development during this significant period. Yet many young children and parents in the United States lack the needed resources to thrive, putting them at greater risk of material hardship, chronic stress, and poor health. Federal and state policies can support vulnerable families and provide a buffer against stress and instability, but most existing programs lack sufficient resources to reach the largenumbers of families who could benefit. Federal and state policymakers must be mindful of the unique needs of infants, toddlers, and families as they consider the policies and investments necessary to change the trajectories for our youngest children.