SACRAMENTO — In a blow to tens of thousands of low-income Californians newly enrolled in Medi-Cal under a provision in the Affordable Care Act, Gov. Jerry Brown on Thursday vetoed a bill that would have limited the state’s seizure of assets from their estates after they die — a legal wrinkle that most only discovered after they had signed up for the health care plan for the poor.

“It is shocking that Gov. Brown has chosen to single out low-income seniors by forcing them into an involuntary loan for their health insurance,” Campbell resident Anne-Louise Vernon, 60, a new Medi-Cal enrollee, said through tears Thursday night. “This is unconscionable, and the governor’s decision not to sign Senate Bill 1124 is penny-wise, pound-foolish and frighteningly hardhearted.”

Brown’s three-paragraph letter to members of the state Senate notifying them he would not sign the bill — which would have limited Medi-Cal estate recovery only to the costs of enrollees’ long-term care — was matter-of-fact. But it did not seem to completely close the door on the issue.

“Allowing more estate protection for the next generation may be a reasonable policy goal,” Brown wrote. “The cost of this change, however, needs to be considered alongside other worthwhile policy changes in the budget process next year.”

For millions of low-income Americans, asset seizure became an issue because of a provision in the Obamacare law, which expanded Medicaid — called Medi-Cal in this state — to low-income adults without children.

But many homeowners who have been laid off, are unemployed or underemployed, and are now getting by on dwindling savings, have said they did not realize that signing up for the health care program for the poor comes with a catch: The state can recover a broad array of costs and assets — including homes — from Medi-Cal recipients 55 and older after they die. SB 1124, authored by state Sen. Ed Hernandez, D-West Covina, sought to limit Medi-Cal recovery only to what’s required under federal law: the cost of long-term care in nursing homes.

Since late August, after both the Senate and Assembly signed off on the bill, Bay Area residents like Vernon remained hopeful that Brown would decide in their favor, even though budget advisers had recommended he oppose the legislation. They warned him that California would lose $15 million annually in general fund revenues as a result.

Estate lawyers say that Medi-Cal reimbursement claims — particularly those involving a recipient’s home — can be avoided through estate planning. But the bill’s advocates say that route can be costly and discriminates against the poor. Contact Tracy Seipel at 408-920-5343. Follow her at Twitter.com/taseipel.