Why the US is attacking Iran now

Vox

5 hours ago

The United States bombed Iran on Saturday night, joining an Israeli-led offensive aimed at demolishing the Iranian nuclear program. The American assault targeted three facilities associated with the program at Natanz, Isfahan, and Fordow — the last of which was widely seen as too fortified for the Israelis to disable without American help.
President Donald Trump, addressing the nation on Saturday night, claimed that the US had won a great victory. The attacks were a 'spectacular military success,' he said, that 'totally obliterated' Iran's nuclear program. No future strikes were planned unless Iran retaliated; if it did, Trump warned, 'future attacks will be far greater and a lot easier.'
But it is very far from clear how true any of this is. We do not yet have conclusive evidence on the damage done to Iranian facilities, and there is at least some reason to believe that key elements of the program escaped US and Israeli bombs.
More broadly, the nature of the US-Iran relationship is long and difficult, with so much mutual distrust and hatred on both sides that it's easy to imagine scenarios by which what's designed to be one-off strikes escalate into something much bigger.
What follows is an attempt to help you understand the big questions swirling around the US-Iran fighting: what we know about the bombing itself, to be sure, but also the deeper context and history necessary to understanding why America is willing to risk yet another war in the Middle East.
1. Why is the US attacking Iran now?
By far the most important reason both Israeli Prime Minister Benjamin Netanyahu and Trump struck now is a perception among their countries' respective security establishments that, in recent months, Iran — suddenly and surprisingly — became vulnerable.
Both countries' security establishments have long seen Iran as an enemy. In particular, Israel has argued that Iran getting nuclear weapons would be disastrous — greatly strengthening a serious foe and, at worst, jeopardizing Israel's very existence.
Yet war with Iran has long been seen as a fearsome prospect. Iran had funded and cultivated formidable proxy forces — including Hamas in Gaza and Hezbollah in Lebanon — that would be sure to unleash their arsenals on Israel if war broke out. Syrian President Bashar al-Assad was also a longtime ally of Iran, and any prolonged Israel-Iran conflict would involve Israel repeatedly flying over Syrian airspace and potentially draw Syria into the war too.
In retrospect, Hamas's October 7, 2023, attacks on Israel ended up triggering a chain of events in which all of those obstacles fell away, one by one.
First, Israel went into Gaza and killed thousands of Hamas militants (in addition to causing enormous civilian casualties). Second, last September, Israel decimated Hezbollah with its 'exploding pager' attack and other operations. Third, in December, Assad's regime suddenly collapsed, and the rebels who took over have not seemed to be spoiling for a fight with Israel. (Separately, Iran's air defenses had also been badly weakened due to Israeli strikes last year.)
So basically, US and Israeli military planners believed that the Iranians were sitting ducks — and had far less ability to retaliate. The logic went: They're vulnerable, so why not stop them from getting nukes now?
Still, Trump remained reluctant to green-light an attack, and when Israel went forward with one, he initially kept his distance. But the quick success of Israel's strikes seemingly confirmed Iran was quite weak. Hawks argued to Trump that this was a golden opportunity to easily destroy Iran's nuclear program with little or no cost to American lives, and he decided to give it a shot.
—Andrew Prokop
2. Did the strikes succeed?
According to the Pentagon, US B-2 bombers dropped 14 30,000-pound 'massive ordinance penetrator' (MOP) bombs on the Iranian enrichment facilities at Natanz and Fordow while submarines launched Tomahawk missiles at a third site at Esfahan. On Saturday night, Trump declared that the three sites had been 'totally obliterated.'
The following day, Chair of the Joint Chiefs of Staff Gen. Dan Caine was a bit more cautious, telling reporters, 'final battle damage [assessments] will take some time, but initial battle damage assessments indicate that all three sites sustained extremely severe damage and destruction.'
Satellite images show heavy damage at all sites, but initial Israeli assessments suggest that the site at Fordow — located deep underground — was not completely destroyed. The UN's International Atomic Energy Agency said in a statement that, given its location, the level of damage at Fordow was impossible to assess without access to the site.
Perhaps more importantly, analysts are skeptical that the Tomahawk missiles were enough to destroy the underground tunnels at Esfahan, where the bulk of Iran's uranium stockpile was believed to have been stored, and it's possible that much of the stockpile was relocated prior to the airstrike.
Secretary of State Marco Rubio conceded in an interview on Sunday that 'no one will know for sure for days' whether the uranium was moved.
Iran's nuclear program definitely suffered a major, perhaps devastating, setback, but the status of its uranium stockpile and its ability to rebuild its destroyed infrastructure are still unknowns.
—Joshua Keating
3. Why are the US and Iran enemies?
Last week, an Israeli airstrike destroyed two 1970s-era, US-made F-14 fighter jets, which were still in the Iranian air force's inventory: a reminder that the US and Iran had once been military partners.
That changed in 1979 when Iran's pro-American autocratic ruler, Shah Mohammed Reza Pahlavi, was overthrown and the regime known as the Islamic Republic, which still rules Iran today, was established.
Resentment of the US ran deep among the revolutionaries: The CIA had organized a coup that overthrew Iran's democratically elected government in 1953 and backed the Shah's autocratic regime in the years that followed. The revolution's hardline religious ideology sought to rid Iran and its region of American political and cultural influence. 'Death to America' and 'death to Israel' have been popular chants at pro-government rallies in Iran since the revolution.
Shortly after the Shah's overthrow, radical Iranian students overran the US embassy in Tehran and took 52 Americans hostage for over a year. Relations between the two countries never recovered.
The US imposed tough economic sanctions against Iran and backed Saddam Hussein's Iraqi regime during the long and devastating Iran-Iraq War in the 1980s. During the 1980s, Iran began building a network of proxy groups to advance its interests throughout the Middle East. Most notable was the Lebanese militia Hezbollah, responsible for the 1983 bombing of a US Marine barracks in Lebanon that killed more than 240 US troops.
After the US invasion of Iraq, Iranian-backed militia groups carried out hundreds of attacks on US troops, often using Iranian-designed improvised explosive devices to devastating effect. The Pentagon has blamed Iran for the deaths of at least 600 US troops during this period. US troops in the Middle East still periodically come under fire from Iranian proxy groups, including, most recently, Yemen's Houthis.
Though the US has long been alarmed by Iran's nuclear ambitions, and the country was included in George W. Bush's 'axis of evil' along with Iraq and North Korea, the last four US administrations have avoided taking military action against Iran's nuclear program, instead relying alternately on escalating economic sanctions and diplomatic negotiations in an attempt to head off an Iranian bomb.
—Joshua Keating
4. Why was the attack controversial among Republicans?
Trump's attack on Iran came after months of factional infighting on the US right. On one side were the hawks: the traditional GOP establishment, who wanted aggressive action against those they deemed America's enemies, including Iran. On the other side was an upstart 'America First' faction — informally led by Tucker Carlson and Vice President JD Vance — that feared being pulled into another Middle Eastern war that doesn't truly serve America's interests.
The two groups battled for months over administration appointments, while their outside allies argued in the press.
Initially, it seemed the America Firsters had won Trump over. In contrast to the 'maximum pressure' sanctions of his first term, he began his second term claiming he wanted serious negotiations over their nuclear program. In April, Trump reportedly waved off an Israeli proposal to strike and pursued talks instead.
But the hawks soon struck back, uniting around a demand that any deal should not allow Iran to pursue any nuclear enrichment whatsoever — a demand Trump soon echoed. No deal on those terms materialized, Trump eventually decided he wouldn't stand in Israel's way anymore, and now he's sent US bombers into the fray too. The hawks are overjoyed.
—Andrew Prokop
5. Was Iran actually racing toward a nuke?
The US intelligence community had previously assessed that Iran halted its efforts to build a nuclear weapon in 2003, but international monitors say Iran has also been dramatically increasing its uranium enrichment activities since 2018, when Trump pulled the US out of the 2015 nuclear deal and reimposed sanctions. And while officially, Iran has insisted that it's only seeking a civilian nuclear program, officials in Tehran have also been talking more openly about the value of actually having a nuclear weapon.
In May, the International Atomic Energy Agency assessed that Iran had amassed a stockpile of 408 kilograms of uranium enriched to 60 percent. Just 42 kilograms could be enough to build an atomic bomb if enriched to 90 percent, a relatively simple technical step. US officials had said that Iran could produce enough uranium for a bomb in one to two weeks and build a weapon in just a few months.
But acquiring the ability to build a bomb and actually building one are not the same thing. In March, Tulsi Gabbard, the US director of national intelligence, testified to Congress that the intelligence community 'continues to assess that Iran is not building a nuclear weapon and Supreme leader Khomeini [sic] has not authorized the nuclear weapons program that he suspended in 2003.'
The government of Israel, which has long advocated military action against Iran's nuclear program, was not so confident. In recent weeks, they had reported gathered intelligence leading them to believe Iran's nuclear weapons program had reached a 'point of no return'. According to reporting by the Economist, this included evidence that Iranian scientists had squirreled away quantities of nuclear material that international inspectors were unaware of, and that these scientists had met with commanders of Iran's missile program about producing a weapon.
The Wall Street Journal and other outlets reported last week that US intelligence agencies had not found the Israeli evidence convincing and stood by the assessment Gabbard had shared in March that Iran had not made a decision to build a nuclear weapon.
This may be a difference in interpretation rather than evidence: Rather than waiting for Khamenei to make an active decision, the Israelis appear to have believed that they had to act once it got to the point that there was no guarantee they could stop it in time if Iran did rush for a bomb.
In any event, Trump now appears to find the Israeli case more compelling than that of his own intelligence agencies. Asked about Gabbard's statement last week, Trump said, 'I don't care what she said. I think they were very close to having a weapon.'
—Joshua Keating
6. How might Iran retaliate?
So far, Iran's military response to both US and Israeli attacks has been underwhelming. Tehran is clearly hobbled by the damage Israel did to its proxy militias, Hezbollah and Hamas, and its ballistic missiles are not capable of threatening the Israeli homeland in the way that many fear.
But there are two things Iran hasn't tried that are, after American intervention, more likely to be on the table.
The first is an attack on US servicemembers stationed in the Middle East, of which there are somewhere between 40,000 and 50,000 at present. Of particular note are the US forces currently stationed in Iraq and Syria. Iraq is home to several Iranian-aligned militias that could potentially be ordered to directly attack American troops in the country or across the border in Syria.
The second is an attack on international shipping lanes. The most dangerous scenario involves an attempt to use missiles and naval assets to close the Strait of Hormuz, a Persian Gulf passage used by roughly 20 percent of global oil shipping by volume.
If Iran either kills significant numbers of American troops or attempts to do major damage to the global economy, there will surely be American retaliation. In his Saturday speech, Trump promised that if Iran retaliates, 'future [American] attacks will be far greater and a lot easier.' An effort to detonate the global oil market would, without a doubt, necessitate such a response: the US cannot allow Iran to hold its economy hostage.
We do not, to be clear, know whether Iran is willing to take such risks — or even if they can. Israeli attacks have devastated its military capabilities, including ballistic missile launchers that allow it to hit targets well beyond its borders.
—Zack Beauchamp
7. Will this be a one-off strike or a wider war?
It is all too easy to see how these initial strikes could escalate into something much bigger — if Iran's nuclear program remains mostly intact, or if Iran retaliates in a way that forces American counter-escalation.
The strike could escalate into a war if the strikes did not fully succeed and the United States decides to finish the job, committing itself to, at minimum, an indefinite bombing campaign — and at most a war of regime change. Or the United States and Iran could become locked in an escalating cycle of violence, with retaliation from Iran provoking more attacks from the United States.
It's also possible neither occurs, and this stays as limited as currently advertised. Key decision points are ahead, like whether Trump orders another round of US raids on Fordow or Iran tries to close the Strait of Hormuz — and it's hard to know which choices the key actors in Washington, Tehran, and Jerusalem will make.
—Zack Beauchamp