Note: Please see correction at end of this article.

Since the November 28 United Nations General Assembly vote to admit Palestine as a non-member state, there has been speculation about whether Palestine will try to join the International Criminal Court. The attempt would face significant but not insurmountable political and legal hurdles. A successful bid, however, would greatly damage the ICC by pulling it into the deep and dangerous waters of the Israeli-Palestinian conflict. This threat could be avoided if Israel were induced to join the ICC as well. Though unlikely, this outcome could represent a milestone in an eventual peaceful settlement.

Palestine could approach the ICC in two ways: by joining as a member state, or by giving the Court jurisdiction over particular crimes on an ad hoc basis. Both options are available only to states, and so both would pose the same legal problems concerning the status of Palestinian statehood, such as where the boundaries of a Palestinian state get drawn and whether it includes Gaza, with its separate and antagonistic government. Except in rare cases when the UN Security Council invokes the ICC’s authority, the Court’s reach is limited to crimes committed in a member state’s territory or by its nationals. So it would be crucial to know whether Gaza and its residents are part of Palestine. Standard legal definitions of statehood require a single government. Moreover, the General Assembly resolution not only affirms a two-state solution based on the pre-1967 borders, but also calls for a contiguous Palestinian state—contradictory and vague language that leaves the actual borders unsettled. In any event, nobody supposes that a two-state solution—which, realistically, would require land swaps—will actually restore the pre-1967 border.

The ICC deals only with a short list of crimes: war crimes, crimes against humanity, genocide, and aggression. Palestinian ICC membership would have a powerful, dual-edged effect. It would give the ICC jurisdiction over not only any relevant Israeli crimes in Palestinian territory, but also crimes committed by Palestinian nationals and attacks launched from Palestine’s territory. For example, rocket attacks targeting Israeli civilians would unquestionably be crimes within the ICC’s jurisdiction. Depending on the circumstances, terrorist attacks on Israel could qualify as crimes against humanity, war crimes, or even acts of genocide. It isn’t hard to see why Hamas has not embraced the proposal of joining the ICC.

On the other hand, Palestinian membership in the ICC could represent a step towards peace, because it would signal Palestine’s willingness to subject itself to a legal framework that forbids terrorist attacks on Israel. Even if Hamas went along, other militant groups would likely try to sabotage a membership bid. In this, they would be on the same side as the Israelis, who fear investigations for war crimes or even apartheid—an unlikely but possible scenario if extremist settlers use violence to create “an institutionalized regime of systematic oppression and domination by one racial group”—the legal definition of apartheid—in Palestinian territory.

Palestine’s other route into the ICC is based on a little-known provision in the Rome Statute—the official name of the ICC’s governing law. It allows states that don’t belong to the ICC to turn particular crimes over to the Court on an ad hoc basis. Normally, the Court has authority over entire “situations,” including crimes by all sides in a conflict. Ad hoc jurisdiction, by contrast, allows a non-member state to invoke the Court’s jurisdiction selectively, over crimes by its adversary, without subjecting its own deeds to ICC scrutiny. This option would obviously represent a much more dangerous possibility for Israel. The country has never joined the ICC, so the Court has no jurisdiction over Israeli actions in Palestinian territory. Ad hoc jurisdiction would change that.

The ICC is unlikely to accept an ad hoc invitation for the Court’s scrutiny of Israeli actions but not Palestinian actions if the violence comes from both sides. This is perhaps why the last time the Palestinian Authority approached the ICC in 2009, it authorized the Court to take jurisdiction over all acts committed on its territory since the Court’s inception in 2002—an amazingly broad request to the Court to examine both sides of the Second Intifada. This past April, the ICC prosecutor’s office announced that it could not act on the 2009 request until the UN or the ICC’s own members clarified the status of Palestinian statehood. After the recent UN vote, Prosecutor Fatou Bensouda issued a non-commital statement that her office would examine its implications.

Netanyahu’s threat to build Jewish settlements in the West Bank, if realized, would be a war crime.

What would happen if Palestine invoked the Court’s jurisdiction over some unilateral Israeli action? The question of Palestinian statehood would then loom large. The Prosecutor would probably conclude that rejecting the Palestinian bid by declaring that Palestine is not a state exceeds her mandate. How could a single lawyer in The Hague defy the UN votes of most of the world’s states, including two-thirds of the ICC’s own members? Assuming the evidence was there, Prosecutor Bensouda would feel compelled to request the Court to open an investigation. That would pass the decision about Palestinian statehood to the judges.

But the ICC judges should conclude that they too lack the mandate to declare Palestine a state and fix its boundaries. The ICC is a special-purpose criminal court, and it would be astounding for it to get out in front of the UN’s own court on a fundamental question about the map of the world. Under the Rome Statute, the dispute would and should go to the assembly of ICC’s 121 member states.

And there it is likely to end. The assembly of ICC states needs a two-thirds vote to accept Palestinian statehood. By coincidence, the number of “yes” votes in the UN included two-thirds plus one of the ICC members. Changed votes by only two member states would scuttle the Palestinian bid.

That seems more than likely. News reports hinted that in the diplomatic run-up to the UN General Assembly vote, some European states agreed to vote yes only if Palestine promised not to go to the ICC. If Palestinian officials went back on their word, those votes would surely change sides. Moreover, ICC action against Israel is far more substantive than the largely symbolic UN move to give Palestine non-member status. It seems unlikely that all the ICC members that voted yes in the UN would also vote yes in the ICC.

Given these impediments, the Palestinians are unlikely to make an ad hoc invitation for the Court’s scrutiny anytime soon. Nevertheless, it remains a live possibility, especially if Israel does something outrageous. Matters could come to a head, for example, if Israel actually goes ahead with its plan to build Jewish settlements in the vital E1 area of the West Bank—the Netanyahu government’s furious, foolhardy threat in response to the General Assembly’s vote. Not only would settlements in E1 cut Palestine in two, but transferring a state’s own people into occupied territory is also a war crime under the Rome Statute. It isn’t hard to imagine that if Israel carries out its E1 threat, the Palestinians will turn to the ICC. Some Israeli lawyers counter that the West Bank is not “occupied,” only “administered.” But few outside the Jewish right accept this hairsplitting legalism.

Palestinian Foreign Minister Riyad Al-Maliki signaled that Palestine is in no hurry to go to the ICC. “As long as the Israelis are not committing atrocities, are not building settlements, are not violating international law, then we don’t see any reason to go anywhere,” he said shortly after the UN vote. But, he added, “If the Israelis continue with such policy—aggression, settlements, assassinations, attacks, confiscations, building walls—violating international law, then we have no other remedy but really to knock those to other places.” This is both an assurance that Palestine does not plan to renew its sweeping blank check of 2009, and a warning that it might approach the Court about new Israeli actions.

Unquestionably, any ICC intervention in the Israel-Palestine conflict would place the ICC in grave peril. All options—declining to prosecute, prosecuting one side in the conflict, or prosecuting both sides—would infuriate key ICC members. Prosecutions would shatter the ICC’s current détente with United States, suck the oxygen out of the Court’s other cases, and introduce incalculably crazy new political spin into a region where calculation is already hard and sane politics is at a premium. Diplomats and politicians would find it convenient to blame the next round of violence on the ICC, however unfairly.

The best outcome, however unlikely, would result from Israel and Palestine both joining the ICC and placing themselves together under the discipline of international law. Doing so would not expose them to meddling from The Hague: the ICC is forbidden from taking cases that member states investigate in good faith on their own. Law enforcement would rest in their own hands, where it belongs. Just as importantly, new members to the ICC start with a blank slate: ICC jurisdiction begins at the moment a state joins, and it only looks forward, not back. If Israel and the still-uncertain Palestinian state both joined the ICC, they would signal—to the world and to each other—a willingness to step toward real negotiations and a two-state solution.

Editor’s Note: A reader has pointed out an error in this article. Under a rule of procedure adopted after the Rome Statute, the ICC will not accept ad hoc jurisdiction over a crime unless the Court gets jurisdiction over the entire situation in which the alleged crime occurs. The article therefore erred in saying “Ad hoc jurisdiction . . . allows a non-member state to invoke the Court’s jurisdiction selectively, over crimes by its adversary, without subjecting its own deeds to ICC scrutiny.” The article argued that the ICC is unlikely to accept one-sided ad hoc jurisdiction; in fact, the ICC cannot accept such jurisdiction. This does not change the practical conclusions of the article. If Israel engages in unilateral criminal conduct, Palestine can request the Court’s ad hoc jurisdiction and accept that the Court will examine the entire situation without fear of implicating Palestinian actions. Of course, if Palestinians are also committing ICC crimes, the Court would be able to investigate and prosecute those as well as Israel’s. The latter situation might happen in a shooting war; the former, in a case where Israel unilaterally moves to expand settlements.