Israel has resumed attacks in force on Gaza this week, breaking a two-month ceasefire and undermining U.S. President Donald Trump's claim that he would end both the Israel-Hamas and Russia-Ukraine conflicts quickly and easily. To some, Trump's seeming empowerment of both Israel and Russia, coming on the heels of former President Joe Biden's earlier failure to deter Russian aggression or use U.S. leverage with Israel to prevent the flattening of Gaza, only proves that the international rules-based order Trump is openly seeking to flout may have never been as sturdy as it seemed. But as I put it in an interview on the American Prestige podcast last week, the rules-based order may be weaker than many may want, but it is stronger than they may think. It can even withstand efforts to break it by the U.S., which disregards rules and institutions - and permits Washington's adversaries and allies to do the same - at its peril. To be sure, as one of the podcast's hosts pointed out, when even a U.S. president who defends the rules-based order, like Biden, fails to bring an ally that is committing crimes against humanity to heel - to say nothing of an advocate of "might makes right," like Trump, failing to do so - it certainly increases the likelihood those crimes will continue. That might appear to confirm the view that rules matter little in international affairs, even when great powers pay lip service to them. But part of the problem is the gaps in the rules-based order itself. In this case, international law does not currently compel third parties to withhold aid from the parties to a conflict committing aggression or crimes against humanity, or come to the aid of those that are the victims of either. That should change - and it could if a Treaty on Crimes Against Humanity were adopted. To be sure, such rules do exist with regard to genocide, which is a very specific crime defined as any one of several acts when those acts are carried out with the intent to destroy in whole or in part a national, ethnic, racial or religious group. The Genocide Convention not only prohibits such acts - including but not limited to wilful killing, bodily harm and infliction of conditions on a group calculated to ensure their destruction - but also requires third parties to prevent and punish such acts. This was the basis of South Africa's effort at the International Court of Justice to seek a stay of hostilities in Gaza until the court made a legal determination over whether Israel was guilty of the crime of genocide there: South Africa claimed it was required under international law to do what it could to prevent or punish what it viewed as a potential genocide, rather than to stand by. But scholars and legal experts are split on whether Israel's atrocities in Gaza constitute genocide. A September 2024 report from the United Nations Office of the High Commissioner for Human Rights argues that Israel's actions are consistent with the characteristics of genocide. So do some rights groups and numerous legal scholars. Others have argued that the crimes fall below this threshold. The International Court of Justice has yet to rule on the matter, while the International Criminal Court's investigation into the situation in Gaza does not include charges of genocide. The debate as a whole underscores how high the bar is set for proving a party is guilty of genocide, largely because it is a crime of "intent." If a prosecutor can't show that the acts were undertaken with the actual intent to destroy the group as such, they don't qualify. And if they don't qualify, then third-party complicity in or incitement of these acts could not trigger criminal prosecutions under the Genocide Convention against leaders of the relevant third-party state. And yet regardless of whether Israel's acts meet the strict definition of genocide, no observer familiar with international humanitarian law could conclude that Israel is not at minimum committing what could reasonably be p...