If California uses Medicaid and its Children's Health Insurance Program as the foundation for implementing the Basic Health Program option in the Affordable Care Act, coverage for low-income adults would be substantially more affordable than in the exchange; federal BHP payments would exceed baseline state costs; and the state could realize budget savings without raising costs for current Medicaid eligibles. However, low-income consumers would access more limited provider networks; the exchange would be smaller; individual insurance premiums could rise; and providers would experience a smaller increase in private reimbursement and a greater increase in public reimbursement than without BHP.