( <a href="https://www.cms.gov/CCIIO/Programs-and-Initiatives/Health-Insurance-Marketplaces/Downloads/2017-08-23-Issuer-County-Map.pdf">Centers for Medicare and Medicaid Services</a> )

On Thursday morning, that last gap was closed. In every county in the country, an insurance provider was ready to handle people enrolling for Obamacare.

As the debate over repealing the Affordable Care Act raged on Capitol Hill earlier this year, the withdrawal of insurers from Obamacare exchanges nationally was a frequent talking point among those advocating for replacing the law. After all, if an individual was mandated to have insurance but no insurance provider existed, that’s a problem. President Trump used the lack of insurers as a talking point in speeches and on Twitter.

It was not just rhetoric. Trump tweeted a quote from the New York Times in April noting the problem. The Kaiser Family Foundation created an animation showing counties without providers over the course of the year; in the spring, as the debate raged, entire states lacked an insurer.

(Kaiser Family Foundation)

Other insurers have since stepped in to provide coverage for each of those counties. But why did this problem emerge in the first place? Cynthia Cox, associate director of health reform and private insurance at KFF, spoke with The Post by phone and explained.

“This year did stand out as being different from previous years,” Cox said. “In previous years, there have been exits, but for the most part in past years the Blue Cross-Blue Shield and Anthem plans stayed on the market. The reason that’s important is because in a lot of rural areas, either the Anthem or the Blue Cross-Blue Shield plan is the only insurer participating in that rural part of the state.”

When Anthem pulled out of the exchange in Ohio in June, it cited “an increasing lack of overall predictability” in insurance markets and concerns about payments from the federal government. The withdrawal was particularly problematic in rural areas, Cox said, because insurers need to have provider networks established in areas to offer service. In counties like Paulding, that’s less likely.

Watch more!

Overall, Cox said, insurers dropped out of the Obamacare exchanges this year mostly because of economic concerns. When the exchanges began in 2014, insurers were losing a lot of money. Since insurers have to make decisions far in advance of their actual coverage — pricing for 2018 happens early in 2017, for example — it meant that insurers were left trying to figure out more than a year in advance whether they could count on making money in the future, having lost money in years prior.

“It can be a two-year cycle, almost,” Cox said, “before insurers can really establish whether they’re on a path to being more profitable or whether they’ve priced wrong, yet again.” Many declined to take that risk — though KFF found that insurance company margins in the first quarter of this year improved dramatically. Cox said that, given this cycle, it wasn’t a surprise that insurers bailed at this point. She also pointed out that the companies stepping in to cover the “bare counties” — those that lacked insurers on the exchanges — were ones that were used to providing coverage to low-income people, which seemed to be an advantage.

She noted that politics probably played a role, too, as Anthem hinted in its withdrawal letter.

“Not clear how much of the bare-county issue is because of political uncertainty, but at least some of it is,” Cox said. After all, committing to covering a county right before, say, the mandate to have coverage is repealed exposes the insurer to a lot of risk.

“In the absence of the political uncertainty, I think the market would be on a path toward stabilizing,” she added. “The political uncertainty is prompting some insurers — even ones that may be profitable — to reconsider their participation for next year. That’s not to say there aren’t still some companies or some parts of the country that are struggling. But as a general statement, the market is on the path toward stabilizing, not toward a death spiral.”

Earlier this week, our factcheckers identified the Trump falsehood that he has repeated with the most regularity.

“Trump’s most repeated claim, uttered 50 times,” they wrote, “was some variation of the statement that the Affordable Care Act is dying and ‘essentially dead.’”