The key to expanding health coverage is in Louisiana

Six years after Obamacare became law, some 30 million Americans still lack health insurance. Louisiana found a trick to get a great number of them signed up for Medicaid.

The policy is based on a simple coincidence: Medicaid and the federal food stamp program have almost the same income threshold, at least in the 31 states that expanded their Medicaid programs under Obamacare.

The Bayou State decided to automatically check to see whether the residents who receive food stamps also qualify for Medicaid — and if so, to reach out and sign them up. This approach will at once lower the state’s uninsured rate (one of the highest in the country) and cut Medicaid’s administrative costs.

The strategy seems so obvious, it’s a wonder no other state has made it policy.

Nationwide, some 8.8 million people eligible for Medicaid have not enrolled. To put that in perspective, it’s more than the number of people eligible for subsidized Obamacare insurance plans but haven’t signed up, more than the number who lack insurance because their states refused to cooperate in the Medicaid expansion, and more than the number who can’t get insurance because they’re in the country illegally.

Increasing the uptake rate for Medicaid is the single most promising way to reduce the number of uninsured Americans — and it requires no action by Congress.

Louisiana already identified 105,000 potential new enrollees.

It’s true that greater enrollment will increase Medicaid spending. But it will eliminate much of the public cost that arises when uninsured residents seek expensive care in emergency rooms.

Louisiana, whose budget shortfall is among the most severe in the country, demonstrates that enrolling more people in Medicaid doesn’t undermine fiscal prudence or good government.

That’s a message other states should hear.

— Bloomberg View