Reader B. J. writes:

Aren’t there two parts to this issue?
1. The power of a state to prohibit out-of-state insurers from selling insurance to its citizens. We may want the federal government to exercise power here for the same reason we want the federal government to exercise similar power in other industries – to prohibit state-by-state protectionism and to force the creation of a common market. If the federal government doesn’t bar all states from engaging in this practice, then each state is deterred from ending the practice on its own because it will lose – i.e., its insurers will be barred from competing in other states while out-of-state insurers will be allowed to compete against its own.
2. The power of a state to regulate insurance that is sold in that state by measures short of the “discrimination” described in (1). This power poses more of a traditional federalism issue: do we want the citizens of each state to decide on their own how to regulate insurance (putting aside (1)) or do we want the federal government to strip the states of this power, and to arrogate it to itself, so that all insurers have to comply with either a uniform standard of a basic “floor” standard on which each state may expand? If you don’t want the federal government taking over the role of basic regulation, then there may not be a need for the federal government to pass a law: each state, on its own, can strike a balance between overregulating (insurance companies leave the state and the price goes up) and underregulating (insurance companies sell shoddy services).
Those who push the “Let Americans buy insurance across state lines” argument tend to get shifty on this and undercut the persuasiveness of their argument. They don’t distinguish between (1) and (2) and they don’t acknowledge that either (1) or (2) – especially (2) – is an expansion of federal power at the expense of the states.
The answer to the argument: “Let Americans buy insurance across state lines!” is: They already can. They CHOOSE not to by (1) using their state governments to bar out-of-state insurers from competing and by (2) using their state governments to regulate the insurance industry. If you want Congress to take action here – especially re (2) – then you need to be able to acknowledge that Congress really is arrogating power to itself and stripping the states – and their citizens – of power.
It’s always baffling to me why, when Democrats argue this issue, they never “talk Republican” by pointing out that Republicans are trying to expand the power of the federal government at the expense of the states. (Ditto with federal “malpractice reform.”) Republicans continually get away with acting as if it is the federal government that imposes burdensome insurance rules or that makes malpractice insurance premiums go through the roof. Nope – it’s Carson City, and Sacramento, and Juneau, and Richmond.
In any event, I agree with (1) and am not convinced of (2) (although I could be to some extent); but I think that one needs to be honest about what he is doing here.

I agree with your point about malpractice reform. I don’t agree with the rest. If state regulations have protectionist effects, Congress can act to free interstate commerce. Whether the regulations are explicitly protectionist or intended to be protectionist doesn’t strike me as important. (I would note, however, that if Congress can act only against explicit state protectionism, state governments will easily be able to circumvent its rules by enacting laws that are intentionally protectionist in their effects but not formally so.)