The United States has provided Israel with billions of dollars’ worth of security assistance and weapons over the past year since Israel began retaliating for Hamas’ October 7, 2023, attack. In addition, the Biden administration has deployed the US military in direct support of Israel.

The Gaza conflict has since broadened into an invasion of southern Lebanon, amid fears of an even wider war. Ahead of Israel’s anticipated response to Iran’s missile attack on Israel earlier this month, the United States said that it would send a THAAD, or Terminal High Altitude Area Defence anti-missile system, to Israel, along with the US military personnel needed to operate it.

The deployment, which places US troops on the ground acting in Israel’s defence, comes after the US military helped defend Israel against two large-scale Iranian missile attacks in April and October.

THAAD is one of the most advanced US missile defence systems. It fires interceptors to destroy incoming ballistic missiles. Each interceptor is estimated to cost tens of millions of dollars and a standard battery contains 48 interceptors.

Separate from the US military’s own efforts in defence of Israel, Washington has significantly increased the amount of military assistance funding sent to Israel and has approved more sales of arms and equipment to the country. Israel had already received more US military aid – and more US aid of any type – than any other country since World War II.

Immediately after Hamas’ attack a year ago, President Joe Biden said he would “make sure Israel has what it needs to take care of its citizens, defend itself and respond”. The spiralling death toll in Gaza – which now exceeds 42,000, according to the Health Ministry there – has led to increased scrutiny of Western military support for Israel.

How has the US military supported Israel since October 7?

Since the attack on October 7 last year, the United States has ramped up military operations in the Middle East, deploying the Navy’s most advanced aircraft carrier, the USS Gerald Ford, to the eastern Mediterranean.

In April, the United States and other allies took part in an operation to defend Israel after Iran launched more than 100 ballistic missiles at the country, as well as about 30 cruise missiles and more than 150 explosive drones, officials later told the Washington Post.

The United States used F-15E Strike Eagles to shoot down about 70 attack drones heading to Israel, while the USS Carney and USS Arleigh Burke, destroyers deployed to the eastern Mediterranean, shot down between four and six ballistic missiles. US troops in Iraq used a Patriot missile defence system to shoot down another, the officials told the Post.

The US military also intervened when Iran attacked Israel again this month, firing at least a dozen interceptors at incoming ballistic missiles, Major General Patrick Ryder, the Pentagon press secretary, said on October 1.

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The Pentagon has not offered estimates for the cost of US military support to Israel in this period. In an estimate released earlier this month, before the deployment of the THAAD system, Brown University’s Costs of War project said the cost of additional US operations in the Middle East since last October was US$4.86 billion ($6.7b).

The Pentagon has not provided an estimate for the cost of the deployment of a THAAD system to Israel. The United States currently has seven THAAD batteries.

How much security assistance has the US provided to Israel since October 7?

United States security assistance to Israel has totalled more than US$200b since the aftermath of World War II.

In 2016, the Obama administration agreed to provide an unprecedented amount of aid to Israel – as much as $3.8b per year over a decade.

In June of this year, the Post reported that the amount of security assistance provided to Israel since the war had hit $6.5b, with nearly $3b approved in May.

Lawmakers green-lit an even higher amount; in April, Congress approved a national security package that Biden said included $14.1b worth of military aid allocated for Israel.

Some estimates put the total spent during wartime far higher. The analysis published by researchers at Brown University assessed that US military aid to Israel in the year since October 7 has exceeded US$17.9b. That figure includes long-standing commitments as well as emergency spending, spanning arms sales, military financing and at least US$4.4b in transfers from US stockpiles.

What weapons and military equipment has the US provided Israel since October 7?

While the Biden administration’s offer of one of its most advanced missile defence systems to Israel brings with it the first significant deployment of US forces to Israel since the war in Gaza began last year, Israel has used US-provided weaponry for its military campaign in Gaza and probably in Lebanon, too.

According to an analysis of visuals released by Israeli forces, Israel probably used US-made 2000-pound (907kg) munitions to kill Hezbollah leader Hasan Nasrallah in Beirut last month.

Many of the details of US military exports are not public, making it unclear how many of the weapons used or recent transfers represent routine supply, as opposed to an escalation intended to replenish munitions used in Israel’s bombardment of Gaza.

Some of the military equipment sales have been publicly announced: at the end of 2023, the White House approved the sale of nearly 14,000 tank ammunition cartridges and equipment to Israel, worth US$106.5 million ($174.78m), and the sale of 155mm artillery shells and related equipment worth US$147.5m.

In March, the Post reported that the United States had quietly approved more than 100 separate foreign military sales to Israel since the previous October – amounting to thousands of precision-guided munitions, small-diameter bombs, bunker busters, small arms and other forms of lethal aid.

Other sales have been approved since the war began but will take years to fulfil. In August, for example, the Biden administration approved US$20b in further weapons sales to Israel, including tactical vehicles and 50,000 mortar cartridges scheduled for delivery starting in 2026, tank ammunition cartridges starting in 2027, and roughly 50 F-15 fighter jets, starting in 2029.

What is the history of US security assistance to Israel?

During the 1970s, Washington provided surges in military aid to Israel as the country rebuilt its forces after the 1973 Yom Kippur War, in which a coalition of Arab nations, led by Egypt and Syria, launched an attack on Israel.

Since then, military aid has remained largely steady if adjusted for inflation, with the stated aim of helping Israel maintain a “qualitative military edge” over its neighbours.

Most US military aid to Israel falls under the Foreign Military Financing programme, which provides grants that Israel uses to purchase US military goods and services. The United States also contributes about US$500m annually for joint missile defence systems. Since 2009, the US has contributed US$3.4b to missile defence funding, including US$1.3b for the Iron Dome programme, which stops short-range rockets, the State Department said last year.

Israel has also been granted access to some of the most coveted US military technology. It was the first international operator of the F-35 fighter jet and used the craft in combat for the first time in 2018.

An Israeli battle tank entering Lebanon from northern Israel. Photo / AFP

Over the decades, US military aid to Israel has mostly been a matter of near-bipartisan consensus. However, the United States has paused military aid or conditioned it in rare moments.

After Israel invaded Lebanon in 1982, President Ronald Reagan halted a shipment of artillery shells and cluster bombs while administration officials determined whether the transfer complied with domestic arms exports laws. The following year, Reagan paused a shipment of F-16s until Israel withdrew from Lebanon.

Why is US military assistance to Israel under scrutiny?

Last month, the Post reported that government watchdogs were investigating some of the administration’s provisions of US weapons to Israel. The forthcoming reports follow concerns from within the US Government that transfers could violate laws prohibiting American military assistance to foreign powers that have committed gross human rights violations or blocked the movement of humanitarian aid.

Israel denies restricting aid access and argues that Hamas bears responsibility for civilian casualties, because the militant group operates in or near civilian areas. The Biden administration has acknowledged that Israel may have violated humanitarian law using American weapons but says security assistance must continue to flow to allow Israel to defend itself.

In May, the White House paused the shipment of thousands of weapons to Israel, including controversial 2000-pound bombs, amid concerns over Israel’s plans to expand military operations in Gaza. The administration subsequently resumed a shipment sending 500-pound (226kg) munitions.

Many US allies – including Britain, Canada, Japan, the Netherlands, Spain and Belgium – have already restricted military equipment transfers to Israel because of legal and political concerns about their potential use to commit war crimes.