Even before the cost estimates and program details have been made public, President Obama’s proposal for expanding high-quality preschool education has encountered criticism from House Republicans. Yet decades of research has shown that well-designed preschool programs more than pay for themselves by giving young children the skills they need to move ahead. The challenge at the federal level will be to make sure that taxpayer dollars flow to proven, high-quality programs instead of being wasted on subsidies for glorified day care.