Is the US willing to pay the price of an Iran-Israel escalation?

As the world waits to see how Iran responds to two recent assassinations of key leaders by Israel, the United States must carefully weigh its role in what happens next.

US President Joe Biden's administration has been preparing for "a significant set of attacks" from Iran and its proxies following the murder of Ismail Haniyeh, a former top Hamas politburo leader assassinated in Tehran last month, as well as the death of senior Hezbollah military commander Fuad Shukr in Beirut.

Increased US military support for Israel suggests rising alarm. Biden has sent warships and a submarine to the Middle East in preparation for an Iranian response, and also sanctioned billions of dollars in arms sales to support what it justifies as "Israel's capability to meet current and future enemy threats."

But further arming Israel is unlikely to dial down threat perceptions among Iran and its proxies.

At the same time, in apparent hopes of warding off any sort of retaliation, Biden has renewed his push for a Gaza ceasefire, which Iran has said could delay its actions. However, Israel has consistently stonewalled the Gaza ceasefire process.

And the message from Tehran has been loud and clear: it will not bow down to Western pressure.

"Such demands (to avoid retaliation) lack political logic, are entirely contrary to the principles and rules of international law, and represent an excessive request," Iran's foreign ministry spokesperson Nasser Kanani said this week.

So is Washington willing to pay the price of an Israel-Iranian escalation in the Middle East?

Indefinite engagement

To Tehran, an attack is necessary because Haniyeh's assassination took place on its soil. Meanwhile Israel is likely to justify its response to this potential attack as necessary "self-defense."

An attack and counter-attack could ignite a cycle of aggression that drags Washington deeper into an escalating regional war.

The US says it doesn't want this. After Israel killed two Iranian generals in Syria in April, the US pressured Israel to avoid an all-out attack on Hezbollah – Iran's chief ally – and determined Israel wouldn't prevail in a long-term confrontation.

Indeed, a conflict on multiple fronts between Israel and Iranian proxies, chiefly Hezbollah, could test the limits of unconditional US support to Israel and its own crisis diplomacy in the region.

Consider the ambiguous nature of Iranian attacks and their timing as well. Iranian militias could take part in any attack of Tehran's choosing, making it difficult for Washington to predict and preempt possible attacks from Lebanon, Iran, Syria, Iraq or Yemen against Israel.

There are also diplomatic costs. The Biden administration is putting its weight behind an "urgent" diplomatic solution between Israel and Hezbollah, and considers the deal as critical to avoiding a larger regional war.

However, it risks losing hard-won diplomatic momentum if Israel pursues a disproportionate military response against Iran, or implements "multi-front battle plans" to justify offensive attacks "anywhere and in any region."

Souring public sentiment

Another factor to consider is public sentiment. There is very little appetite among Americans for the US to get involved in another war. Polls show most Americans are against sending US troops to defend Israel. Public support for such a move has steadily declined since Israel's onslaught on Gaza began last year.

Thus, any Iran-Israel escalation could raise the stakes in Washington when considering whether to participate in an unpopular war and risk alienating scores of young voters ahead of the November presidential polls.

Taxpayer dollars are an additional limiting factor. Congress and the US public have been increasingly at odds over Washington's spending on "endless wars" – a reference to years of US invasion in Afghanistan and Iraq that has yielded little tangible benefit.

US-Iranian escalation could prompt Washington to beef-up its military finances for Israel and use up hard-earned taxpayer money to fight another war.

Israel's war on Gaza has prompted thousands of Americans to protest US funding for the war, with many refusing to pay their taxes. All these factors could make it difficult for Washington in the event of Israeli-Iranian escalation.

Endangering US troops

Iran-Israel escalation could also endanger US military assets in the region. This includes scores of US troops stationed across small-scale military bases in the region.

Regional escalation and a widening of Israel's 10-month war could inject significant intensity into future attacks. After all, Iran-aligned militias attacked US forces dozens of times in Iraq throughout the opening months of Israel's war on Gaza.

The widening of Israel's war with Iran could signal the entry of more powerful actors, such as Hezbollah, raising serious questions about Washington's strategic interests in the Middle East.

Can it stop Israel from attacking Hezbollah, the same group that the US seeks to engage diplomatically? And what is Washington's own endgame amid Israel's raging war on Gaza and beyond?

Alternative options

Rather than continuing to generously arm Israel, the Biden administration has some immediate response options at its disposal. It can use weapons sales as leverage to pressure Israel towards a ceasefire.

For months, billions of dollars in unrestricted military aid have hardened Israeli attitudes towards a Gaza truce, and spurred a significant trust deficit between Israel and Hamas. Now, that trust deficit risks upending high-stakes mediation efforts in Doha.

Thus, holding back Israeli weapon supplies could send a powerful signal to far-right Israeli Prime Minister Benjamin Netanyahu's leadership that the US now wants the raging war to end on its own terms.

US should also impose long-overdue penalties on Israel for its systemic violations of international law, and torture committed by military units in Gaza. All these are gross violations of the Leahy Law, which requires the US by law to end assistance for military units involved in rights abuses.

Time running out

Time is running out. Washington joined Egypt and Qatar for a new round of ceasefire talks this week to end the war in Gaza, an outcome Biden claims could prevent an Iranian attack on Israel.

But much of the optimism over a US-brokered ceasefire is overblown. Tehran has refused to take part in direct talks toward a ceasefire, and officials close to Hezbollah confirmed to Reuters that an Iranian retaliation was incoming.

This is important because Washington is pushing for more lines of communication with Tehran to limit or prevent an Iranian strike at all costs. But it is counting on a ceasefire process that lacks credibility and has been used by Israel to pursue assassinations and stonewall mediation progress.

Today, US failure to rein in its major ally Israel is putting its own interests on the line. The threat of a wider regional war is undermining Washington's crisis diplomacy, risks long-term damage to US military assets in the region, and has left little leverage to prevent Iran's imminent attack on Israel.

Washington shoulders blame for the same escalation it seeks to avoid.