Just as choice and competition make products and services less expensive in the rest of the economy, they can do so in health care. We must substantially expand Americans’ freedom to choose their own health insurance—both in public and private programs. We should gradually convert the Medicaid program from its current single-payer form into one in which enrollees receive tax credits to buy private insurance. And we should strengthen Medicare Advantage, the market-based form of Medicare whose consumer-driven structure has incentivized insurers to offer broader benefits, lower out-of-pocket costs, and better health outcomes than traditional Medicare does.