It can sound trite if you just say citizens need to be educated for democracy to work, but for him it wasn't trite. It was really this strenuous challenge to citizens to use their moments of leisure, which he defined as time away from work, to collect the facts that were necessary for full democratic participation.

I think the answer has to do with the fact that [Louis D.] Brandeis was a consistent critic of bigness in business and in government.

Initially the papers said that the fact that Louis Brandeis was picked because he was Jewish. The New York Sun said he's the first Jew ever picked for the bench - a long and bitter fight expected in the Senate over confirmation.

Louis Brandeis really inspired me to write this book [Louis D. Brandeis: American Prophet]. It was a crazy deadline. The editor said I'd miss the hundredth anniversary unless I pumped the thing out in six months, because I'd been delaying and dilly dallying for so long. So he both inspired me to get up early and write.

[Louis] Brandeis is often painted as an acolyte of judicial restraint, or the view that judges should uphold laws whether or not they like them.

The historical resonances are sharp. [Louis] Brandeis is nominated on Jan. 28, 1916. Confirmed on June 1. Waits 125 days between nomination and confirmation, which remains an unbroken record, although Merrick Garland will surpass it in July, if my math is right. Anti-Semitism was definitely not the central reason for the opposition, which tended to focus more on his anti-corporate radicalism, but it was a theme.

Do you think Bernie Sanders, for example, is citing Theodore Roosevelt as the progenitor of his critique of the banks when actually Roosevelt wanted to keep the banks together and regulate them.