Before becoming president, Shimon Peres said he would pardon him, and many Israelis, from the left to the centre-right, have long seen him as a potential peace partner. But the most famous Palestinian prisoner in Israeli detention says that today peace with Israel is "impossible".
The comments by Marwan Barghouti came in an interview with an Algerian newspaper.
Barghouti was a leader of the Second Intifada, and since 2004 has been serving five life sentences plus 40 years in an Israeli prison. His convictions included five counts of murder and membership of a terrorist group. He was also a leader of the First Intifada, during which he was arrested by Israel and deported to Jordan, where he lived until allowed to return home in 1994.
But something of a Jekyll-and-Hyde figure, between the intifadas he developed a reputation as a would-be peacemaker. During the mid-1990s he was involved in numerous meetings with Israeli politicians from across the political spectrum and with the Israeli peace camp. He made a deep impression on many of them, and was for a negotiated two-state solution with Jerusalem as a shared capital.
When it has looked likely that Barghouti could be freed as part of a deal to free Gilad Shalit, left-wing group Gush Shalom placed advertisements declaring: "Freeing Gilad Shalit is a moral act. Freeing Marwan Barghouti is a wise act."
Marwan Barghouti gained a reputation as a dove
The current instability in the Palestinian leadership, especially following the release of the Palestine Papers, makes the question of Barghouti's current politics all the more important. Polling has suggested that he could receive two thirds of the votes if he were to stand for Palestinian president.
If the PA leadership were to fall, it would be an urgent necessity for Israel to know what kind of a leader Barghouti would be and, given his ability to outdo Hamas in the popularity stakes, whether it may be worth freeing him.
So how does one interpret Barghouti's latest declaration? Have the hopeful Israelis been backing the wrong horse? That is one distinct possibility - that dazzled by his openness to peace more than a decade ago, people have been believing that his "real" beliefs were frozen during the intifada and will, once again, guide him. Another possibility is statements like his latest are directed at a Palestinian audience, and he realises that there is no choice but negotiations.
A third possibility is that he is a pragmatist. He viewed violence as the best course of action on some occasions, and talks as best on others. This would make him something of a loose cannon, but still possibly a peace partner.