Beyond that, you need to realize that the law was never intended or expected to cover everyone. Undocumented immigrants aren’t eligible, and any system that doesn’t enroll people automatically will see some of the population fall through the cracks. Massachusetts has had guaranteed health coverage for almost a decade, but 5 percent of its nonelderly adult population remains uninsured.

Suppose we use 5 percent uninsured as a benchmark. How much progress have we made toward getting there? In states that have implemented the act in full and expanded Medicaid, data from the Urban Institute show the uninsured falling from more than 16 percent to just 7.5 percent — that is, in year two we’re already around 80 percent of the way there. Most of the way with the A.C.A.!

But how good is that coverage? Cheaper plans under the law do have relatively large deductibles and impose significant out-of-pocket costs. Still, the plans are vastly better than no coverage at all, or the bare-bones plans that the act made illegal. The newly insured have seen a sharp drop in health-related financial distress, and report a high degree of satisfaction with their coverage.

What about costs? In 2013 there were dire warnings about a looming “rate shock”; instead, premiums came in well below expectations. In 2014 the usual suspects declared that huge premium increases were looming for 2015; the actual rise was just 2 percent. There was another flurry of scare stories about rate hikes earlier this year, but as more information comes in it looks as if premium increases for 2016 will be bigger than for this year but still modest by historical standards — which means that premiums remain much lower than expected.

And there has also been a sharp slowdown in the growth of overall health spending, which is probably due in part to the cost-control measures, largely aimed at Medicare, that were also an important part of health reform.