The implementation of Obamacare is an awfully difficult subject to cover. It requires following developments in Washington and in the 50 states, each with its own unique challenges and politics. It requires speaking with people in government and business, with insurers and employers and advocates, with the people who provide health care and, of course, with the people who use it. It’s a sufficiently difficult task that few writers have even tried to summarize it all in one place.

Ezra Klein and Sarah Kliff of the Washington Post have. Their article is as fair as it is throughly reported. If you want to know what's happening with health care reform, you should read it, although you should also be warned: If you seek clarity on what Obamacare will look like in 2014, or validation for your one-sided views on the law, you probably won’t find it. One theme of their article is the genuine uncertainty over how some parts of the law will work. Another is the significant difference in perception among people who are actually working on it. Obama administration officials are certainly confident, for what seem like good reasons. They have detailed, well-designed plans for everything from making a website consumers can use to recruiting young people to sign up for coverage. But outside the administration plenty of smart observers are sketpical. And they, too, seem to have good reasons. In between are the state officials working overtime (literally) to make sure law works for their constituents. They are anxious, although it’s impossible to tell if that’s because they are struggling or because they are simply being ultra-cautious. I imagine it's a bit of both.

Of course, not all state officials are trying to make the law work. Some are doing their best to fight it—most obviously, by making sure their state Medicaid programs don’t expand to cover all poor people (rather than certain classes of them). The instant, most devastating impact of this decision is to deny health insurance coverage to some of the neediest people in the country. A new Kaiser Family Foundation report, prepared by researchers at the Urban Institute, calculates that as many as 6.4 million Americans will miss out on coverage because their states won’t expand Medicaid.

But, as Klein and Kliff point out, the decision not to expand Medicaid might create secondary problems, as well. Here’s why: Imagine you live in a state where officials have decided not to expand their Medicaid, and that you are not eligible under the existing criteria for the program. If your income is above the poverty line, or about $11,500 for an individual, then you can still get subsidized private insurance through one of the new Obamacare exchanges. This is the part of the law that states cannot block. But if your income is below that level, you won’t be eligible for anything. That's going to confuse, discourage, and anger people. “How do you explain this in a way that seems fair and reasonable, that the higher-income people get help but you don’t?” one pollster told Klein and Kliff. “Advocates on the ground are really struggling with that group. They want to have a positive message but don’t know what to say.” The danger is that, frustrated with stories of people who tried to get coverage but couldn’t, even those who would qualify for insurance won’t bother.

This particular part of the Klein-Kilff story happened to get the attention of Ben Domenech, the conservative writer and editor of The Transom. It was, he said, among the “multiple warning signs for the difficulty of making the law a reality.” That’s true. But, of course, it’s trouble because Republican lawmakers want it that way.