Taxes and Clear Statement Rules

Balkinization:  Clear Statement Rules and Taxes, by Gerard N. Magliocca (Indiana-Indianapolis):

Ever since [last] Thursday, I've had an uneasy feeling about Chief Justice Roberts' opinion. Now I think I know why.

The most interesting part of his ruling, I think, is the explanation of why letting Congress tax commercial inaction is not problematic given that Congress cannot command us to act in commerce. The Chief gives three reasons for this distinction.

1. Nothing in the Constitution says that inaction may not be taxed
2. The courts would invalidate a tax that was high enough to amount to a penalty
3. Taxes are less coercive than commands

What is missing from this list? Do you see it? The answer is that taxes are also subject to a robust political check. In other words, because taxes are usually unpopular, Congress will be more hesitant to use that means than others to achieve its ends. Why is this missing from the Roberts opinion?