A California bill to replace health insurance companies with universal government-funded care is advancing to a vote in the full Senate.
But Democrats who back the measure have not identified a way to pay for the estimated $400 billion annual cost.
The single-payer health care bill cleared a hurdle Thursday when it passed the Appropriations Committee in a 5-2 party-line vote.
SB 562 has energized liberals at a time when President Donald Trump and Republicans in Congress are looking to overhaul former President Barack Obama's health care bill.
Supporters say a single-payer system would redirect insurance company profits and administrative costs to patient care.
Insurance companies and business groups say the bill would upend the health care system and its costs would cripple businesses.
A vote in the state Senate is expected next month.