The Dissent speaks to the penalty or tax isse

Opinion Journal quotes from the argument of those who opposed the Obamacare tax ruling:

The provision challenged under the Constitution is either a penalty or else a tax. Of course in many cases what was a regulatory mandate enforced by a penalty could have been imposed as a tax upon permissible action; or what was imposed as a tax upon permissible action could have been a regulatory mandate enforced by a penalty. But we know of no case, and the Government cites none, in which the imposition was, for constitutional purposes, both. The two are mutually exclusive. Thus, what the Government's caption should have read was "ALTERNATIVELY, THE MINIMUM COVERAGE PROVISION IS NOT A MANDATE-WITH-PENALTY BUT A TAX." It is important to bear this in mind in evaluating the tax argument of the Government and of those who support it: The issue is not whether Congress had the power to frame the minimum-coverage provision as a tax, but whether it did so.

... So the question is, quite simply, whether the exaction here is imposed for violation of the law. It unquestionably is. The minimum-coverage provision is found in [the Affordable Care Act's individual-mandate provision], §5000A, entitled "Requirement to maintain minimum essential coverage." (Emphasis added.) It commands that every "applicable individual shall . . . ensure that the individual . . . is covered under minimum essential coverage." (emphasis added). And the immediately following provision states that, "[i]f . . . an applicable individual . . . fails to meet the requirement of subsection (a) . . . there is hereby imposed . . . a penalty." (emphasis added). And several of Congress' legislative "findings" with regard to §5000A confirm that it sets forth a legal requirement and constitutes the assertion of regulatory power, not mere taxing power. . . . 

We never have classified as a tax an exaction imposed for violation of the law, and so too, we never have classified as a tax an exaction described in the legislation itself as a penalty. To be sure, we have sometimes treated as a tax a statutory exaction (imposed for something other than a violation of law) which bore an agnostic label that does not entail the significant constitutional consequences of a penalty—such as "license" or "surcharge." But we have never—never—treated as a tax an exaction which faces up to the critical difference between a tax and a penalty, and explicitly denominates the exaction a "penalty." Eighteen times in §5000A itself and elsewhere throughout the Act, Congress called the exaction in §5000A(b) a "penalty." . . ....

What the majority has done is make taxes  a form of penalty.  That should make them more difficult to sell.  But what Roberts and the other four conservatives have also done is limit the commerce clause.  When the liberals get over their celebratory hangovers they may contemplate how they will deal with that as they strain to pass "taxes" to accomplish their objectives.