In September, I wrote about the 1798 insurance requirement that supporters of the 2010 health care bill frequently attempt to use in order to establish that early congresses of the United States understood the interstate commerce power to allow them to require individuals to engage in commerce. I demonstrated that the two mandates were very different from each other, and that the 1798 act could not serve as a precedent for the 2010 bill. (I also pointed out that there was no reason to assume that whatever was done by an early Congress was necessarily constitutional.)
Well, I have something to add. In support of the 1798 law, there would have been no claim (or any need to claim) that the commerce power allows people to be compelled to engage in distinct, new acts of commerce or that they are engaged in certain markets whether they want to be or not, and regardless of what they do or do not do. The first reason for this (apart from what I wrote about in September) is that the 1798 law concerned an actual, existing commercial relationship between people and a ship, and it regulated the conduct of a party to that contract to adjust for the consequences of that relationship. The end arose out of and the means applied to the same class of actual commercial relationships -- it should not be difficult to see why this might be considered a genuine regulation of commerce.
Additionally, the ship itself would have been a creature of commerce -- an artificial person, created for the purpose of commerce (more or less a corporation), not a natural person. I will not say that simply because ships and corporations are artificial persons which exist for the purpose of commerce that the federal government may require of them anything it desires, but when such a vessel is the subject of a federal law, it is much more reasonable to think that it would be a valid application of the interstate commerce power than if the law applied to all persons. (If someone were to respond that the individual mandate could then properly apply to everyone who engages in commerce at all, I would wonder whether that person is giving the issue full and honest consideration. Under that approach, the objective would not be related to the basis on which the regulation applies to a person, as it would when the behavior of employers is regulated in order to affect the effect of employment on the condition of employees -- it would simply leverage the rightful liberty of every person to engage in commerce in order to compel us all to obey an unrelated command.)
One way or another, the regulation affected only actual commerce, unlike a requirement that everyone buy health insurance.