But over the past few weeks, the news has started to roll in the other direction. Enrollment has surged beyond expectations. Costs are coming in lower than predicted. Various reports say the number of uninsured Americans is falling. Now it's good news snowballing, and it's critics who increasingly seem to have missed the mark with their warnings of inevitable collapse.

For all the partisan rancor over Obamacare, there's always been a lot of agreement about what the possibilities were—how the law could fail and how it could succeed.

So when Republicans spent years predicting that Obamacare would fail and people would reject it, there were always distinctly possible events that could get us there. Maybe premiums for 2014 would be too high, and people wouldn't want to buy the coverage. Or the website would stay broken and people couldn't buy it even if they wanted to. Or people would be so turned off by the site that they wouldn't sign up even after it was fixed. Critics warned of a "death spiral," which is an insurance term—both sides knew what it meant and what might cause one.

Critics still promise that the law cannot work as intended, but the evidence keeps piling up in the other direction. The opportunities for failure keep falling away, and worst-case predictions keep going bust.

There was no death spiral, nor will there be one. And there was never going to be a "death panel." Some people's premiums went up, and a lot of people had their plans canceled, but people didn't reject the law's coverage options—at least 7.5 million people picked a plan through the law's exchanges, and another 3 million got Medicaid coverage. People were willing to come back to HealthCare.gov, and enrollment spiked at the last minute—just as the White House had predicted.

The next big warning is about premiums for 2015. Critics say premiums will skyrocket because not enough healthy people signed up this year. Some insurers have said they expect hikes in the double digits in parts of the country.

At the same time, though, some insurers are looking to expand their presence in the exchanges next year, and others have indicated they might jump in for the first time, after taking a wait-and-see approach this year. So far, no large plans have said they intend to leave the exchange marketplace. All of that indicates that insurers see the market as stable. And more plans competing for more new customers will likely keep premium increases in check.

The law's detractors are right about some big gaps in the enrollment data. The White House's 7.5 million figure isn't a fiction, but it's inflated. We don't know how many people paid their first premium, or how many were previously uninsured.

Both of those questions are important—the number of people who paid their premiums will be the actual enrollment number, and the reduction in the number of uninsured people will determine how well the law is doing on its most fundamental goal. But neither answer will likely move the law back across the survival threshold it has already crossed.

The most authoritative count of uninsured Americans has come from the Census Bureau, which announced earlier this week that it's changing the way it asks about health insurance. The new questions are more likely to be accurate, but the timing of the change means it will be all but impossible to look for trends in the census data.

Other data sources, though, suggest that the law is indeed reducing the number of people without insurance, contrary to some Republicans' warnings that it would lead to a net loss in insurance coverage.

According to Gallup, the percentage of Americans without health insurance has fallen from 18 percent in to 15 percent. The polling organization says roughly 10 million people have gotten covered, including about 4 million who are covered for the first time. The Urban Institute says 5.4 million Americans have gained insurance coverage since the law's new options came online.

But these are all policy points. It'll be hard to declare victory for Obamacare if the law remains unpopular, and if its unpopularity costs Democrats control of the Senate this year. And public approval isn't budging. In every public opinion poll, pluralities disapprove of the ACA.

There are, however, a few smaller indications that people don't personally fear Obamacare the way they used to.

Gallup, for example, asks its respondents not only whether they approve or disapprove of the law, but how they think it will affect their family's health care situation in the long term. For about two years, a growing plurality said it would hurt them. Now, those numbers have flipped.

In results last week, 32 percent said the law would make their personal situation worse—an all-time low, and 8 points lower than Gallup's last survey. The number of people who said the law would make no difference shot up to 42 percent, and the number who thought it would help them ticked up slightly, to 24 percent.

The breakdown of how people think the law will affect the country's health care system hasn't changed, and it largely mirrors approval or disapproval—pluralities think the law will make things worse, and disapprove of it.

Yet nearly one-third of respondents in a new Reuters poll said Democrats have better ideas on health care, compared with 18 percent who chose Republicans. Democrats gained ground and Republicans lost it since Reuters' previous poll, conducted before the last-minute enrollment surge.

That's just one poll, of course. Democratic incumbents still aren't likely to embrace Obamacare, and it remains a powerful weapon for motivating the Republican base—which may be all the party needs.

Democrats aren't in a place where they can declare victory on Obamacare, but victory is also falling further out of reach for the law's critics.