Commentary Tennis star Novak Djokovic famously (or, depending on your perspective, infamously) refused to get vaccinated against Covid-19 as a condition for entering Australia to play in the Australian Open. Djokovic’s refusal prompted National Review’s Kevin Williamson and Charles Cooke to engage each other in an online debate over the merits of government-mandated Covid vaccination. Williamson finds such mandates to be less objectionable than does Cooke. Especially because each man is thoughtful and principled, reading their exchange is worthwhile. This issue is a serious one and must be dealt with accordingly, as is done by Williamson and Cooke. The Williamson-Cooke exchange prompted Washington University economist Ian Fillmore to share with me his thoughts about vaccination mandates. Here’s part of an email that I recently received from Ian (which I share with his kind permission): I have seen the argument “You didn’t oppose HepA vaccine mandates in the past, so why are you so upset about …