"If the Supreme Court strikes down ACA in part or as a whole, and you did not like the law in the first place, do not assume you should be happy," writes Tyler Cowen. "It is far from obvious that we will end up with something better."

I think that's wise advice. Now, as someone who supports the Affordable Care Act, I probably would think that's wise advice, wouldn't I?

But here's my question for opponents of the act: What do you really think happens next? Back when Democrats were pushing single-payer plans, Republicans like President Richard Nixon were arguing for plans with an employer mandate. Then President Clinton embraced an employer mandate and Republicans turned to an individual mandate. Then President Obama embraced an individual mandate and Republicans moved to get the individual mandate ruled unconstitutional and taken off the table forever. And they might succeed.

But then what? I don't think it's particularly controversial to say that the United States of America is, one day, going to have universal or near-universal health insurance. Having 50 million uninsured Americans, 25 million underinsured Americans, and 150 million Americans who are one layoff away from losing their health insurance  is not a sustainable long-term equilibrium.

I also don't think it's particularly controversial to say that if the Affordable Care Act falls apart, the next time Democrats get a crack at passing universal health insurance, they're going to want to do it in a way that avoids Republican obstruction and can't be questioned by the Supreme Court. The most obvious policy path that achieves both goals is to expand public programs like Medicare and Medicaid, as that can be done through the filibuster-proof budget reconciliation process and it can't be touched by the Supreme Court.

I don't like that future on either policy grounds or humanitarian grounds. That's single-payer through a messy process of attrition, and it could take decades. But it does seem like the likeliest long-term path if the individual mandate gets ruled unconstitutional or the Affordable Care Act is repealed. But perhaps someone can tell me what I'm missing. I'll post the best answers later.