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IT TOOK MANY months of mediations to reach a ceasefire agreement between Israel and Hamas, Gaza’s Islamists. So far the fragile truce—signed on January 15th—is holding. But difficult details must yet be resolved. Evidence from thousands of ceasefires from across the world suggests when these agreements are most likely to end in success or failure.
Data from The Ceasefire Project, a research group, includes all ceasefires involving at least one country between 1989 and 2020. Of the 2,203 ceasefires in the study, roughly half ended successfully (with a formal peace agreement, for example) or stretched beyond the end of the study. A third of the ceasefires failed (fighting resumed or the parties withdrew from the agreement). The rest either never started or there was not enough information to determine their outcome (see chart 1).
More than 100 of the ceasefires involved Israel, including 39 between Israel and Hamas—the most recent in 2020. More than 20% of these agreements met their objectives or were replaced by a new agreement. But they failed to stop fighting breaking out again.
Each conflict has unique circumstances that determine whether a ceasefire holds. But the researchers note that successful ceasefires tend to have three things in common. The first is a political process to address the underlying cause of the violence. In late 2023, for example, Israel agreed to temporarily pause its offensive in exchange for hostages. But without political engagement, the truce remained brief and transactional: the fighting resumed seven days later.
The second is the presence of a monitoring system (by an international organisation, for example). Four-fifths of ceasefires without one resumed fighting within a year. Such systems may help to ensure that both sides stick to the agreement. Alternatively, warring sides who agree to such a system might already be more committed to lasting peace. (America and Qatar are keeping a close watch on the implementation of the current Gaza ceasefire; the EU is involved in monitoring some aspects.)
A third factor is whether the ceasefire lasts beyond the initial “fragility window”. Ceasefires that fail often do so within the first few days. But those that make it to 100 days with fewer than 25 people being killed in fighting have a better chance of leading to lasting peace. And that fragility window shrinks if the deaths threshold is lower (see chart 2).
A failed ceasefire can be better than nothing: violence after a period of peace tends to be less intense than it was before. And any reprieve in fighting can allow aid and assistance to reach civilians.
The next test for Israel and Hamas will come on February 2nd, when talks resume on the next stage of the ceasefire—which includes the withdrawal of Israeli troops from all of Gaza and the release of more hostages. Whether the ceasefire can endure will depend on those discussions.■