“Young people just don’t vote.” This has been America’s shrugging cliché for a century. Though Bernie Sanders has engaged millions, like Barack Obama before him, conventional wisdom holds that young voters are inherently unreliable.

But tell that to J. J. McCarthy, the young cowboy galloping across the Nebraska plain to cast his “virgin vote” in 1884.Or George Washington Albright, the 15-year-old slave tiptoeing from cabin to cabin, spreading news of emancipation and beginning his climb to the Mississippi State Senate. Or Mattie Thomas, living a half-century before women won the ballot, but using all of her 23-year-old influence to get her beau to vote for her preferred party on Election Day, 1868.

Young people used to vote. And march, and speechify, and riot, in wild elections from the 1830s to 1900. Children, teenagers and young adults found personal meaning in public life. Politicians recruited “warm, fresh blood,” as one organizer recalled, seeking new votes, as well as skills with brickbats and bowie knives (for when rallies turned rough). There was a time when young people were the most coveted demographic in politics.

From Manhattan newsboys to Arizona miners, young people fueled American politics at their loudest. Millions joined in boozy elections, often driving turnouts over 80 percent. Even the quietest presidential contest, in 1852, drew far more voters than the election of 2008, the largest in recent memory. Americans viewed politics with what the humorist Donn Piatt called “all the fanaticism of religion and all the fascination of gambling.”