A simple question at a Bernie Sanders town hall last spring sparked a debate new to prime time: Should incarcerated people be allowed to vote? Sanders said yes—his home state of Vermont (and its neighbor, Maine) are the only states to give all people in prison that right. Later, Joe Biden said no.

Yet in a country awash in political polling, the views of those who are most affected remain a mystery: the 2.3 million people behind bars. Do they want to vote? If given the right, who would they vote for? What issues do they care about most? No one’s ever really asked.

This is why The Marshall Project partnered with Slate to conduct the first-of-its-kind political survey inside prisons and jails across the country. Now that criminal justice is a campaign issue and many states are restoring voting rights to those convicted of felonies, we asked thousands of incarcerated people across the country for their opinions on criminal justice reform, which political party they identify with and which presidential candidate they’d support. We heard from more than 8,000 people.