From Israel's Ramla prison south of Tel Aviv, Hana Shalabi moved on Sunday to the relative freedom of Gaza. Her negotiated release came, not by coincidence, after a 44-day hunger strike. The case provides a new example of how effectively Palestinians can use the moral high ground.

Ms Shalabi, 29, spent 25 months, from 2009 until last October, in "administrative detention" for alleged Islamic Jihad activity, jailed but neither charged nor tried. Released in the prisoner exchange last October, she was rearrested in February, and held, again with a military court's approval but neither charges nor trial, for allegedly resuming Islamic Jihad activism. Israel claims that administrative detention is needed to protect intelligence sources, but nobody can pretend that it provides even a semblance of due process.

This time, however, Ms Shalabi had a new approach, inspired by Khader Adnan, an Islamic Jihad member who ended his 66-day hunger strike in exchange for a promise of early release. The day she was arrested, Ms Shalabi began her own hunger strike. Like Mr Adnan she was offered a shortened sentence if she would eat; she held out for release, and on Sunday she got her way on negotiated terms.

To be sure, some rights groups are not entirely happy with agreements such as the one Ms Shalabi and the Israelis reached, noting that she had to promise to stay in Gaza for three years, although her family home is in Jenin in the West Bank. The International Committee of the Red Cross called on Israel "to comply with international humanitarian law ... which prohibits Israel, whatever its motives, from forcibly transferring Palestinians to another territory".

Lawyers will doubtless continue to argue about such details, but on the political level Ms Shalabi has won a valuable victory for the Palestinian cause. Israel is said to hold over 300 Palestinians without charges; many have now reportedly launched their own fasts.

The Palestinian prisoners' movement needs to reassert this moral force. Hamas and Fatah continue to squabble, violence consistently proves counterproductive and Israel has now imposed solitary confinement on Marwan Barghouti, one of the most credible proponents of reconciliation, for his political statements.

But the prisoners of Israel's arrest machine who are being held without trial have discovered a way to assert their human dignity by, in effect, daring Israel to let them die behind bars without due process of law. In such cases, even the most obtuse of observers worldwide can see which side has the true moral legitimacy.