We can only hope that in their forthcoming book on tax justice, Saez and Zucman will say the things they didn’t say in their op-ed. We can hope that they’ll help us with two empirical questions. First, what was really happening in the era of high rates? Second, why don’t they think we should worry about how taxes will affect growth? Furthermore, we can hope that they will explain their underlying philosophical position—what do they mean by “justice,” and why do they think we should share their views?