Hamas leaders have declared that any cease-fire deal in Gaza must include the release of Marwan Barghouti, a popular Palestinian leader who has been in an Israeli prison since 2002. In fact, Barghouti might be the key to more than a cease-fire. He may well be the best hope of reviving the two-state solution.

Barghouti, 64, has been a member of Fatah, the dominant faction within the Palestine Liberation Organization (PLO), since he was a teenager. He cofounded Fatah’s shabiba (youth movement) decades ago, before rising to lead the Tanzim, the faction’s grassroots cadres that uphold the organization’s local-level leadership. Though he has spent more than two decades incarcerated, he remains well-known and widely respected among Palestinians.

I first met Barghouti in the 1980s with my cousin, Mubarak Awad, an advocate of nonviolent activism. Given his interest in the effectiveness of nonviolent struggle, Barghouti had been given the Arabic edition of "Nonviolent Soldier of Islam," a translated biography of Khan Abdul Ghaffar Khan, an ally of Mahatma Gandhi in the Indian independence movement. Barghouti was keen to learn not only about Khan, but about anyone, from Gandhi to Martin Luther King Jr., who might offer useful insights into how to achieve Palestinian liberation.