Progressive reformers failed to gain support to implement compulsory health insurance in the US after WWI. Modeling results presented in this paper, using a lifecycle model with sickness risk and precautionary savings, support the conclusion that existing voluntary insurance plans were adequate and welfare-enhancing in the US, that compulsory health insurance as proposed would not be welfare-enhancing, and that Americans' preference to self-insure during most of their working lives was rational, utility-maximizing behaviour.