After spending a month on the defensive during the government shutdown, Republicans are back on the offensive with a full-blown assault, yet again, on ObamaCare.

However, after years of dire warnings that were largely relegated to the theoretical sphere, Republicans finally have concrete problems with the Affordable Care Act to hold up as proof they were right all along. The federal insurance exchange website was a lemon in need of immediate, extensive repair; some people are, despite the president's past claims, being pushed off their existing health plans; and there are fresh concerns that the law will cause premiums to spike for some who buy their own coverage.

With all those problems simultaneously plaguing ObamaCare, Democrats have been forced to defend the law at every turn. That dynamic was on full display Tuesday during a House hearing in which Republicans hammered Marilyn Tavenner, head of the Centers for Medicare and Medicaid Services, over the law's botched rollout.

Unlike some of the Tea Party–tinged screeds directed at the law over the past three years, the pointed questions in the hearing "didn't come off as just more unfocused anger at Obamacare," according to Politico. Instead, Republicans were "more methodical about raising other issues that could become problems down the road."

At one point, Tavenner apologized for the law's poor debut, adding, "I want to assure you that can be fixed, and we are working around the clock to give you the experience that you deserve."

Yet the health-exchange website is just one piece of the law Republicans have attacked with renewed vigor.

"If you like your health insurance, you can keep it," Obama declared in promoting the law years ago. Except millions of people who purchase their own insurance — meaning they don't get it through their job or the government — have found the opposite to be true. Hundreds of thousands of people have already received cancelation notices stating that their coverage did not meet the more comprehensive standards mandated by ObamaCare.

In addition, some people have found that their premiums will actually go up under the law. David Frum, writing at The Daily Beast, said he had been pushed off his old plan only to learn that "not only will I pay more, but I have had to divert many otherwise useful hours to futzing around with websites and paperwork. "

That exposed an underlying flaw in the law, he went on, in that moderately well-off people — not just the richest of the rich — will wind up paying more to subsidize the sick and elderly.

The ACA was ingeniously designed to deliver benefits to Democratic constituencies and impose costs on Republican ones. The big surprise in the ACA rollout is that this design is going awry. It's not only plutocrats and one-percenters who will find themselves worse off; not only the comparatively affluent retirees enrolled in Medicare Plus programs. Self-employed professionals who earn too much to qualify for ACA subsidies will soon discover what I have discovered: They are paying more for a worse product. [The Daily Beast]

"These problems can't be fixed through a tech surge, and they're not just a glitch in someone's health-care coverage," House Ways and Means Chairman Dave Camp (R-Mich.) said during Tuesday's hearing. "While a website can eventually be fixed, the widespread problems with ObamaCare cannot."

That is, more or less, the argument the GOP would now like to make: That the website is just one superficial flaw in a law that is flawed in its very bones.

Still, premiums are projected to fall overall under the law, giving Democrats a strong counterargument. A report last week from the Center for American Progress projected that premiums through the exchange marketplace would be 16 percent lower than previously expected, translating into $190 billion of savings over the next decade.

How are those competing narratives — that premiums will rise and fall at the same time — reconcilable? Essentially, it's a tradeoff. By boosting the pool of insured individuals, there will be more competition to drive down prices. At the same time, well-off people who purchase their own insurance will have to increasingly subsidize the new enrollees.

In short, the ACA's tweaks to the insurance market "are raising insurance premiums for some people who did well under the old system and lowering them for many of the people who were locked out or discriminated against," wrote The Washington Post's Ezra Klein. So while Frum may wind up paying more for coverage, someone at the lower end of the income spectrum will pay less.

In addition, those who have to pay more for insurance — who, let's remember, still constitute a small minority of the population at about 5 percent — should get more bang for their buck in terms of quality of coverage, as well as tax credits to help them offset the costs.

Democrats can also point to the state-level changes under ObamaCare as a sign the law is working as they hoped.

States that created their own exchange marketplaces have been relatively successful so far at extending coverage to the previously uninsured. And with ObamaCare's expansion of Medicaid taking hold, thousands of low-income Americans are signing up for coverage at rates far beyond what the administration imagined.

Far more Americans stand to gain from ObamaCare than lose. Still, the first impression of ObamaCare has not been a good one, which isn't helped by the fact that Obama got caught fudging the truth about everyone getting to keep their existing plans if they so desired. Unless Democrats can highlight the silver linings to ObamaCare's otherwise abysmal rollout, the impression that the law is a failure could stick.