The human toll of the Israel-Hamas war has been truly terrifying. Israel has responded to Hamas’s murder of thirteen hundred civilians this past Saturday by launching a campaign of one-sided, vengeful slaughter of innocent Palestinian civilians. Israel has killed more than fifteen hundred Gazans, at least five-hundred of whom are children, and wounded more than six-thousand through indiscriminate bombing that’s outdone the violence of the Ukraine, Iraq, and Afghanistan wars in its ferocity.

But this not-even-week-old conflict has the potential to get much, much deadlier and more dangerous. There is a strong possibility that the war could escalate, widening into a region-wide conflict — one that could wind up dragging even the United States into the fighting.

The latest disturbing news is that just before midnight last night, the Israeli military announced that everyone north of Wadi Gaza had twenty-four hours to evacuate to the region’s south. The implication is that Israeli forces will take no responsibility for whatever happens to whoever is left in northern Gaza by the end of today. The order is being widely interpreted as a sign that the far-right government of Prime Minister Benjamin Netanyahu is about to launch a ground invasion, and one that will almost certainly result in the mass murder of civilians: the United Nations says that moving 1.1 million people in that short amount of time is “impossible.” It has called for the Israeli government to rescind the order, which it says would transform “what is already a tragedy into a calamitous situation.”

It seems very likely that, as bloody as the Israeli air offensive has been so far, we are about to witness killing and destruction on an even bigger scale. And that should be extremely concerning, not just because the murder of any civilians, whether Israeli or Palestinian, for the crimes of their government is wrong and unacceptable, but because this could very well lead to the war spilling outside of Israel-Palestine and becoming a far more dangerous regional conflict.

A brutal ground offensive could well draw Hamas’s regional allies, the so-called “Axis of Resistance” made up of Iran, Hezbollah, and Syria, to enter the conflict in some form. Hezbollah, for one, has said explicitly that it would respond to a ground offensive led by Netanyahu by intervening in the war.

While the other regional actors haven’t laid out the same red line, scenes of even greater indiscriminate carnage than now and news of skyrocketing casualties in Gaza would put extraordinary pressure on them to get involved. That’s not just because of neighboring Arab nation’s sympathy for the Palestinians, but because in terms of reputation, they cannot be seen to simply stand by and let a long-standing adversary get away with such actions with impunity. Nearby Arab states such as Saudi Arabia have, at the behest of the US, chosen to pursue normalization with Israel. The Iranian government, which offers financial and military support to Hezbollah, the non-state military force based primarily in Lebanon, has taken advantage of rapprochement between Arab states and Israel to present itself as the last standing regional champion of Palestinians.

Escalation is not simply a far off possibility. Hezbollah and Israel exchanged rocket fire shortly after the Hamas attacks. Syria and Israel likewise exchanged shelling earlier this week, after the Israeli military reported being hit by mortar shells and artillery from within the borders of its northeastern neighbor. Yesterday, Israel launched attacks on Syria’s two major airports, further escalating the conflict.

Meanwhile, Iran’s hard-line president, Ebrahim Raisi, recently phoned his Syrian counterpart, Bashar al-Assad, and called for “all the Islamic and Arab countries” to work together on “stopping the crimes of the Zionist regime against the oppressed Palestinian nation.” On the call, Assad agreed on the “necessity of rapid action at the Arab and Islamic levels to protect the Palestinian people.” Iran’s foreign minister reiterated that “the continuation of war crimes against Palestine and Gaza will receive a response from the rest of the axis.” Hezbollah and Iran-backed militias have already started mobilizing fighters in Syria.

The Biden administration, in anticipation of Israel’s adversaries entering the war, quickly deployed warships, aircraft carriers, and fighter jets to the region to deter regional powers from intervening. But deterrence may not be enough, and should the “Axis” intervene in the war in earnest and Israel ends up fighting a multifront war against several adversaries, it’s hard to believe Joe Biden would resist the domestic political pressure — particularly with one eye on his flagging reelection chances — for the United States to launch its own intervention.

Even a limited intervention from the Iranian government alone — say, by providing weapons or logistical support to Hamas — could trigger a widening of the war. Successive Israeli governments have threatened to attack Iran to stop its nuclear program, an outcome that’s become more and more likely thanks to both Donald Trump’s tearing up of the Iran deal and the Biden administration’s failure to negotiate its restoration. The result has been not just soaring tensions between Iran and the United States and Israel, but that the only viable nonmilitary alternative to halting Iran’s nuclear program is effectively dead — making the military solution long pushed by hawks appear (quite wrongly) like the only option.

Netanyahu in particular has spent virtually his entire career salivating over a war with Iran and looking for any excuse to justify one. The United States and Israeli militaries, after all, have been recently carrying out massive joint military exercises simulating war with Iran.

Should any potential Israel-Iran hostilities draw the United States into out-and-out fighting, all bets are off. For one, Iran-backed militias in Iraq have threatened to strike US targets, should America get involved in the Gaza war. Not only would this mean a terrible loss of US lives, but would likely trigger doubly fierce US retaliation that could soon send hostilities spiraling.

It’s also easy to imagine, for instance, Russia deciding to take advantage of this kind of situation and get involved in a limited, indirect way, even as it remains bogged down in the Ukraine war. Not only is Iran a long-standing an important partner, one that’s been deepening ties with Russia and has provided key military support for its invasion, but the temptation would be great for Moscow to try to turn the tables on Washington by playing a similar role to that of the United States in Ukraine: providing munitions and other support to bleed the United States, both out of retaliation and to shore up the success of its own war effort.

Needless to say, this is by no means the most likely scenario, and every other scenario just described depends on a host of factors: from the scale, nature, and human toll of whatever Netanyahu ends up doing, to individual choices by all the actors involved, all of whom — including Netanyahu — could well decide that embroiling themselves in a wider war would mean paying a higher cost than the alternative, whether that’s damage to reputation from doing nothing, the weakening or even defeat of an ally, or missing a chance to harm a long-running adversary. Then again, they just as easily might not.

But the point is that these are above-zero possibilities. Some more likely than others and already showing signs of happening, and none of us can know how the escalation dynamics might play out. That’s particularly the case in an unpredictable tinderbox like the Middle East, where Palestinian justice remains an important concern for the populations whose sentiments even authoritarian leaders have to play to. Even the most limited of these outcomes, like, say, “merely” Hezbollah getting involved in the war in response to an Israeli ground invasion, would mean many, many more lives lost, including on the Israeli side.

This is why all energies must be directed right now toward securing a cease-fire, and pushing US and other Western leadership to restrain Israel from launching a ground invasion, as well as carrying out any further killing of civilians. You should support this not just for the sake of Palestinian and Israeli lives, but to prevent a tragedy from spinning into a catastrophe.