Kamala Harris is beginning to offer the first definitive clues of a new economic vision — one with the potential not only to offer a unifying vision for the Democratic Party but also to serve as the foundation for a governing philosophy that crosses party lines. In recent years, both parties have broken with a markets-know-best default setting. The question is, what comes next? One influential school of thought, advanced by Ezra Klein and Derek Thompson, argues for increasing the supply of essentials such as housing, health care and clean energy, in part by using government to break the choke...
