By contrast, Marcus said, the rationale for a broccoli mandate is that eating more green vegetables would "improve people's health," which would in turn "improve overall worker productivity, thus affecting our national economy." He noted that the Supreme Court has rejected such productivity-based reasoning, precisely because it could apply to almost any activity.
But that is not the only way to justify a broccoli mandate. You could also argue that the failure to eat green vegetables imposes costs on others because it makes people less healthy and therefore more likely to need medical treatment.
That sort of argument becomes increasingly powerful as the government's role in health care expands. When the government forces you to pay for other people's medical treatment, either directly through taxpayer subsidies or indirectly by requiring insurers to take all comers and charge them the same rates regardless of health, you have a financial stake in other people's lifestyle choices, including their diets, their exercise levels, their sleep patterns, their oral hygiene and their risky habits.
These decisions, aggregated together, have a substantial effect on health care spending, which the Obama administration has vowed to control. Imagine the fun that Congress could have coming up with mandates aimed at coercing healthier lifestyles once it has a constitutional blessing as well as a fiscal justification. Even if it sticks to regulating purchases, the possibilities for meddling will be wide and varied, ranging from food to recreational activities.
If you value your freedom to spend your money as you choose, you should hope the Supreme Court rejects the Obama administration's open-ended view of the Commerce Clause -- no matter how you feel about broccoli.