Hamilton, a musical biography of the bastard immigrant who became the first U.S. Treasury secretary, ranks among the most inventive, emotionally gripping theater pieces ever written. But as giddily virtuosic as Lin-Manuel Miranda’s music and lyrics are, it’s the casting concept that reveals the profundity of his vision. Without comment or apology, black and Hispanic actors (including Miranda, as Hamilton) portray every Founding Father.

That bold move, paired with a score that’s rooted in hip-hop and contemporary R&B, has helped the show appeal “to new, younger, and more diverse audiences who had otherwise felt left out of the Broadway scene,” notes Judith Rodin, president of the Rockefeller Foundation. And with ticket prices for the runaway hit topping $1,000, Miranda is making sure those audiences aren’t shut out—for example, by offering heavily discounted tickets to students from high schools across New York City.

Taken together, the show’s concept, message and efforts to expand its audience are Miranda’s way of asserting that America’s ideals belong to everyone. And that’s arguably the most optimistic, civic-minded statement any artist is making today.

A version of this article appears in Fortune’s April 1 issue as part of the World’s 50 Greatest Leaders feature, our annual list of world-changing leaders in business, government, philanthropy and beyond. Click here to see the entire package.