Ahead of Monday‘s official commemoration of Martin Luther King Jr., actor and activist John Cusack, journalist and public intellectual Naomi Klein, and writer and artist Molly Crabapple were among those who joined Sen. Bernie Sanders on the campaign trail in New Hampshire over the weekend to meet with voters and explain to rally-goers why their preferred candidate—coupled with the grassroots movement he now leads—represents something extremely rare in U.S. politics.