Lemme translate this:
A reform aimed at getting more [young people] to buy coverage would have to make it even more stupid for them to remain uninsured. Some reformers would do so with a firm individual mandate backed with a stiff penalty. But the Supreme Court last year said a legal requirement to buy coverage would be unconstitutional and transformed Obamacare’s mandate and penalty into a tax on the uninsured. And since forcing people to buy a product they don’t want doesn’t make for great politics, that penalty (now tax) was in any case set much too low to fundamentally change the financial calculation for most people.
Roughly: Do not assume that John Roberts is on Barack Obama’s Christmas card list. This is one devil of a pickle that the Supreme Court has gotten the Democratic party into; the President is not exactly in a position to raise taxes on anybody, let alone young people.