Israel is defending itself against a foreign invasion by a U.S.-designated terrorist organization hellbent on killing every single Jewish man, woman, and child on Earth. That is not hyperbole; it is literally in Hamas’s founding charter .

For the record, the call to kill Jews around the world comes in addition to the clause vowing the obliteration of the state of Israel . Per the Convention on the Prevention and Punishment of the Crime of Genocide, genocidal acts are “committed with intent to destroy, in whole or in part, a national, ethnical, racial, or religious group, as such.”

Over the weekend, Hamas terrorists carried out the largest mass killing of Jewish people since the Holocaust. They murdered 900-plus, mostly civilians. They kidnapped, raped, tortured, and desecrated human bodies. They beheaded babies and burned children alive. They took the elderly and infants hostage. And they brazenly filmed themselves doing it, daring the world to care. Among many other crimes against humanity, Hamas is openly guilty of genocide.

Israel has mounted a defensive operation to annihilate Hamas’s threat once and for all. At the moment, with the raw footage of the mutilated bodies, the captive children, and the elderly women held hostage, the vast majority of world opinion still stands with Israel, although of course there are notable exceptions . Over time, however, as these visceral images fade, Israel’s enemies will inevitably fall back on the charge that Israel’s response, whatever it ends up being, was somehow " disproportionate ." And the media will likely amplify that message until it becomes a dominant narrative. So, before anyone has a chance to do that, and while there is still some compassion for the innocent slain, let's review the law.

Under international humanitarian law , the principle of proportionality forbids attacks in which expected civilian casualties will be excessive in relation to the anticipated military advantage gained.

Proportionality has nothing to do with the relative number of people killed on both sides, and the reason for that is clear: When you judge the appropriateness of an attack based on the number of people who died, you do not protect civilians; you incentivize human shields.

Israel anticipates that its response to these unprecedented attacks will gain the important advantage of ending Hamas’s genocidal reign of terror once and for all.

International law recognizes that the possibility of civilian casualties is an unfortunate but expected element of even lawful missions such as this one; it simply requires Israel to try to minimize the number, which the IDF is doing, including with the use of targeted precision strikes and by warning civilians to leave certain neighborhoods, or even head out of Gaza entirely across the border it shares with Egypt. The IDF does not target civilians.

Hamas, however, knows that people either misunderstand or willfully distort what proportionality means and assume (for no good reason) that it has something to do with the relative number of dead bodies on each side. Hamas leaders consistently take advantage of this dangerous misconception by exploiting their own civilian population, including and especially women and children, and purposely placing them in harm’s way. They are already doing this now. They do this with sickening disregard for the lives of their own people, in order to inflate the body count and make things look even more “disproportionate” to an undiscerning media. Beware this behavior and this trap, because under the kind of effects-based, nonlegal analysis people tend to use, this inhumane calculus is all to often rewarded with sympathetic PR pieces.

To be clear: From an international law perspective, Israel does not only have the right to a shock and awe response, under the Convention on the Prevention and Punishment of the Crime of Genocide, but it also has an affirmative obligation to make sure that "Never Again" means "Never Again."

That does not mean Israel will repay barbarism for barbarism. One of the chief complaints in the false charge of disproportionality is that it isn’t a fair fight, as if that matters when you try to commit genocide, because the IDF is strong enough that it could flatten Gaza in five minutes. But it doesn’t.

Israel will continue to do everything it can to minimize civilian casualties, not only because that is the law but because, unlike the enemy it currently faces, Israel has a moral compass. Israel’s response, however, may yet end up being asymmetrical, for the simple reason that Israel does have better technology and weaponry. That is what happens when you spend decades investing in the safety and security of your people, instead of wasting all of your time and money building terror tunnels underground.

But in the face of a depraved and genocidal enemy hellbent on another Holocaust, it is hard to imagine that Israel's response will be anything but disproportionate. Israel can and must hit back hard enough that Hamas is completely obliterated. Every single drop of blood that will inevitably spill, including any incidental loss of civilian life, as heartbreaking as it is, is entirely on Hamas’s hands. And every single person who continues to show support for Hamas even now, knowing everything that we know, seeing everything that we have seen, is nothing more than a terrorist supporter.

May the memories of all those murdered by Hamas be a blessing, and may God avenge their blood while keeping every innocent person safe.

Mark Goldfeder is director of the National Jewish Advocacy Center.