Obamacare is back in the news today as the Supreme Court hears oral arguments in King v. Burwell, a case that could invalidate subsidies in states that use the federal insurance exchange -- a development that could unravel the entire law.

No one knows for sure how the Court will rule on this second major challenge to the Affordable Care Act -- it ruled in 2012 that the individual mandate was constitutional -- but there is one thing we do know: No matter what the Court decides, it won't change public opinion on the law.

How can I say that with absolute certainty? Because nothing, literally nothing, has moved the needle on perceptions of the law in years. Check out this trend line via Pew that traces views on the law going back to 2010.

The stasis reflected in the Pew numbers are the same story you find in any long term trend on opinions about the ACA. Just for comparison's sake, here's the Kaiser Family Foundation's trend line on the same question:

Remember that both of those charts reflect some major moments in the law: the 2012 Court decision, the 2012 election and the failed rollout of healthcare.gov to name three. And yet, with a month-long anomaly or two, the numbers never move. Unfavorable views outpace favorable views although rarely by a wide margin.

Why does public opinion never change on Obamacare?

For one, the law has been debated to death -- meaning that if you are paying even marginal attention to politics and policy you likely have a pretty strongly-held view on it. And, new information isn't going to change that opinion since you are more likely than not to dismiss it as "spin" coming from the side with which you disagree.

For another, the ACA has become a proxy for President Obama and his broader policies. If you like Obama, you like the law. If you don't, you don't. And neither of those opinions have anything to do with what's actually in the law or how its implementation is being handled.

Regardless of what explanation you ascribe to -- and it might be a bit of both, honestly -- one thing is very clear: The cake is totally and completely baked on Obamacare. Nothing, not even a second Supreme Court case, will change what people think of it.