Just how big was the September 12 protest march? It’s hard to say. The estimate of “tens of thousands” is pretty conservative, given what I saw when I was down on the Hill that day. Talk of “millions,” on the other hand, seems quite outlandish.

One objective measure that could offer some perspective is the Metro ridership number for Saturday. Although they are often sparing with other information (such as their employees’ compensation), Metro posts the figures for daily rail riders (and for bus riders, with a month delay).