The lion's share of the ACA is now considered constitutional, for all intents and purposes (or "for all intensive purposes" for those who attended Texas public schools). That does not imply that it's "good" legislation or "bad" legislation. It simply means the constitutional argument cannot be made in criticism of it.
Let's remember how Mitt Romney justifies opposing the ACA despite crafting a Mini-Me version of it as governor of Massachusetts (though his law was actually the forerunner to the ACA, so maybe that makes the ACA a...Mega-Me?). First, he says that his health reform plan was "completely different" from Obama's - it wasn't. Then, he says he opposes it because it's not something the federal government is allowed to do.
Except that the motley crew of John Roberts, three Old Jews and a Wise Latina have declared that it is something the federal government can do. So what is Mitt's new rationale? If he still opposes the ACA, why did he implement a near-identical plan in Massachusetts? Is he saying he regrets doing that? That his only substantive achievement while in office was actually a bad thing?
Rick Santorum said at one debate that it would be terrible to have Mitt Romney standing on a debate stage next to the President in the fall precisely because he could not serve as an effective critic of the biggest animating force in the Republican Party - the Affordable Care Act. And Santorum was right. Santorum opposed the ACA and the very idea of anything like the ACA from the get go - constitutional or not, it was categorically wrong for reasons of Santorum's moral and economic philosophy. But Romney's only legitimate criticism of Obamacare, because of his words and his actions for the bulk of his political career, was its constitutionality, and that criticism ceased to exist today.
Basically correct. However, the Constitutional issues are not over. Today, it was declared a tax. Another Constitutional issue is immediately raised, "Can a tax be waived from equal application by bureaucratic fiat?" That could be litigated for years.
