At Fellowship Chapel in west Detroit, Bernie Sanders delivered a thundering battle cry for the progressive movement before a crowd of nearly 2,000 people, squeezed into wooden pews and crowded into an overflow room.

The town hall had the feeling of a revival meeting led by Sanders, who preached with the same urgency a message he delivered repeatedly on the 2016 presidential campaign trail: the system is rigged against the American people.

But in Detroit he punctured the bleak prophecy with a glimmer of hope. 

"What this whole debate is about is what constitutes human rights: the right of freedom of speech, freedom of religion," Sanders said. "Franklin Delano Roosevelt said we need economic rights, not just political rights. And healthcare is a human right. 

"The good news is that more people agree with us."