I enjoy plenty of government services (my library, my bus, the mail) but if I had to pick an absolute favorite thing the US government does, it might be “fund Gavi.” Gavi is the international body, funded by rich governments and philanthropies, that bankrolls and organizes the distribution of life-saving vaccines in the Global South. Countries become eligible if their gross national income per capita is under $1,810. That’s lower than you might think — a lot of countries that we consider quite poor, like Bangladesh or Kenya, are too rich to qualify for Gavi support. Those who get aid...