Why the World Fears a War Between Israel and Iran

An all-out war could entangle countries around the world and threaten the global economy.

By Victoria Kim

As the number of adversaries that Israel is fighting has piled up over the past year — Hamas in Gaza, the Houthis in Yemen and Hezbollah in Lebanon — the most worrisome prospect has been the potential for a war with Iran.

The two nations, which do not share a border, have long been waging conflicts by proxy, subterfuge and sabotage.

Each of the militant groups Israel is concurrently fighting is backed by Iran. The indirectness was always by design: Despite being regional rivals, each wanted to avoid what was sure to be a costly, existential direct confrontation.

Now, with Israel planning a retaliatory attack after Iran’s ballistic missile barrage of unprecedented scale and scope on Oct. 1, a war seems more likely, alarming the international community and countries in the region.

Here is why a war is so concerning.

Israel and Iran have two of the region’s most formidable militaries.

Israel has one of the world’s most technologically advanced militaries and is among the top military spenders globally as a share of gross domestic product. Israel’s arms industry produces weapons at such a high capacity that last year it produced enough to export a record amount despite its war in Gaza, according to researchers. Israel is also heavily backed by the United States, which has supplied more than 29,000 guided bombs, artillery rockets and assorted missiles since 2009.

Iranian Revolutionary Guard members march at a parade in Tehran last month.

Credit...Arash Khamooshi for The New York Times

Iran’s armed forces are among the largest in the Middle East, with at least 580,000 active-duty personnel and about 200,000 reservists, according to an assessment last year by the International Institute for Strategic Studies. Iran has made the development of precision and long-range missiles a priority for decades and has amassed one of the largest arsenals of ballistic missiles and drones in the region. The country also has a sizable inventory of drones, with ranges of up to 1,550 miles and the ability to fly low to evade radar.

A war could draw in the U.S. and Gulf States.

A spiraling conflict between Iran and Israel, one of the United States’ closest allies, could pull U.S. forces positioned throughout the region into the fray. Iran’s foreign minister, Abbas Araghchi, said in a social media post that “anybody with knowledge or understanding” of Israel’s plans to attack Iran should be held accountable. President Biden has indicated that he is aware of Israel’s plans.

Senior Pentagon officials have been debating whether the increased U.S. military presence, intended to avert a wider war, has been inflaming the regional conflict by emboldening Israel. The Defense Department said in late September that it was sending a few thousand additional U.S. troops to the region, to bolster the 40,000 who are in place. This month, the United States sent Israel an advanced missile defense system known as the Terminal High Altitude Area Defense, or THAAD, with about 100 American troops to help operate it.

A Terminal High Altitude Area Defense unit deployed last year in Guam during a multinational joint military exercise.Credit...Chang W. Lee/The New York Times

Iran’s foreign minister has made oblique threats against countries that host U.S. forces, which include Qatar, the United Arab Emirates, Bahrain and Kuwait. Iran’s mission to the United Nations warned in a statement this month that “should any country render assistance to the aggressor, it shall likewise be deemed an accomplice and a legitimate target.”

The economic fallout could be devastating.

Israel has told the United States that it will not attack Iran’s nuclear or oil facilities in its expected attack. Even so, that assurance does not preclude Israel from taking aim at Iran’s oil installations in any future rounds of escalation, and the fallout could be immensely destabilizing for the global economy.

Though highly unlikely, an Israeli strike on Iran’s oil facilities could prompt Iran or its proxies to target refineries in Saudi Arabia or the U.A.E. Another remote scenario that analysts fear is Iran threatening the passage of tankers through the Strait of Hormuz, through which oil produced in the Persian Gulf is shipped to the world.

A shock to the global oil supply could lead to surging gas prices, dampen hiring and investment and push economies toward recession. The reverberations would be particularly damaging for poorer nations that depend on imported oil.

A mural in Palestine Square in Tehran on Wednesday shows photos of hostages in Gaza. The mural says that none of them will be freed after the killing of Yahya Sinwar, the leader of Hamas in Gaza.

Credit...Arash Khamooshi for The New York Times

There is a lot of room for miscalculation.

In past years, the prevailing presumption for Middle East watchers was that both Iran and Israel wanted to avoid direct conflict.

This April, Iran’s attack involving more than 300 drones and missiles, in retaliation for Israel’s killing of seven Iranian officials in Syria, shattered that supposition. That surprised Israel, which had miscalculated the severity of Iran’s response, according to U.S. officials. Israel’s measured response at the time appeared to bring the tit for tat to a conclusion well short of war.

Israel may now be more willing to risk war with Iran after the barrage earlier this month targeted civilian areas in addition to military ones. The longstanding framework of deterrence appears to have collapsed, leaving each country in danger of misjudging the other’s response and overstepping at each turn.

Victoria Kim is a reporter based in Seoul and focuses on breaking news coverage across the world. More about Victoria Kim