Which brings us back to the 1.9 million approved in October or November in states that actually expanded Medicaid. If we are correct in our assumptions above, we can estimate that, in the absence of an expansion, 10 percent fewer would have been approved for Medicaid in those states. That gives us an actual estimate for Medicaid enrollment due to the ACA’s expansion of that program: 190,000.

We should remember that there are people who applied through the exchanges and were found eligible for Medicaid who aren’t included in this estimate. We should also emphasize that the numbers for November are still preliminary. On the other hand, we (necessarily) lumped together people who applied for Medicaid and CHIP in our data.

More importantly, several states that expanded Medicaid advertised this fact heavily and probably attracted a disproportionate number of people who were already eligible for Medicaid but didn’t know it. While it’s probably fair to attribute these enrollees to Obamacare, they would keep their coverage in the event of a repeal, and might not figure heavily in November. Regardless, even if you double the estimate — which seems awfully generous — that’s only 380,000 new Medicaid enrollees due to Obamacare, a far cry from 4 million.