Tensions between Israel and Iran have increased since President Donald Trump unilaterally pulled the United States out of the Joint Comprehensive Plan of Action— the 2015 accord to wind back Iran's nuclear program in return for sanctions relief — in 2018.
European signatories to the JCPOA have been unable to effectively lift the renewed embargoes on trade with Iran, prompting Tehran to gradually restart uranium enrichment as the deal crumbled in mid-2019. Meanwhile, tit-for-tat confrontations on Iranian and US proxies in the Persian Gulf, along with Israeli attacks on Iranian proxies in Syria and Iraq, have escalated.
Israel and Iran have been antagonists since the 1980s. But, after the US's 2003 invasion of Iraq and the formal withdrawal of American troops in 2011, the regional balance of power was broken, leaving the Middle East without a clear hegemon. That created a vacuum that has brought the countries into increasing conflict.
Despite their aggressive rhetoric, officials in neither country seek an all-out, direct war. But differences in perception, deteriorating commitment to the vestiges of the JCPOA, and the vagaries of elections in Israel, Iran and the US all ratchet up the prospect that an inadvertent clash could escalate the conflict.
Ali Vaez, an Iran analyst for the International Crisis Group, told DW that the conflict has become "a screw that only turns in one direction, getting tenser and tenser over time."
"There are serious risks of miscalculation that could push the parties into even greater and more direct confrontation," Vaez said.
Iran's expanding influence
In recent years, Iran has expanded its influence in the region. In Syria, it has bolstered the operations of President Bashar Assad. In Iraq, it has supported political parties and various militias since the US invasion in 2003 and, according to anonymous US officials cited by The New York Times, has recently been building up an arsenal of short-range ballistic missiles there. In Yemen, it has backed the Houthis against Saudi Arabia; in December the US claimed it had intercepted a transfer of advanced Iranian missile parts to the Houthis.
To Israel's north, Iran has maintained strategic support for Hezbollah, Lebanon's strongest political party, with a paramilitary wing widely considered to be more powerful than the Lebanese army.
Tehran is trying to establish a balance in a region where Saudi Arabia and the United Arab Emirates massively outspend Iran militarily and Israel already possesses nuclear weapons, Trita Parsi, the executive vice president of the Washington-based think tank Quincy Institute for Responsible Statecraft, told DW. With a limited, aging air force that cannot compete with regional and US combat aircraft, missiles are Iran's only conventional deterrent.
Series of attacks
Israel has long carried out undeclared strikes on Iranian targets in Syria, but recent months have seen officials publicly claim the operations, intensify the attacks and expand the theater of war.
Israel's military hit more than 200 Iran-backed targets in Syria in 2017 and 2018. In a rare public admission in late November, the military claimed one of the largest strikes in recent years on Iranian and Syrian targets in Damascus, in the midst of a flare-up of violence with Gaza.
The intensity of the operations has increased since the latest standoff in the Persian Gulf started in May, when the United States deployed military assets around the Strait of Hormuz, a number of tankers were sabotaged and seized, and rival drones were shot down in what appeared to be active if indirect engagement between forces operating on behalf of the US and Iran.
Vaez said Iranian officials had come to the conclusion that Israel was behind an October attack on an Iranian-flagged tanker in the Red Sea in what would be an expansion of military operations. In November, Prime Minister Benjamin Netanyahu said Israel would widen its operations to Yemen "to prevent Iran from entrenching itself in the region."
This year, Iraq's government blamed Israel for targeting Iran-allied Popular Mobilization Forces positions in Iraq, along with Shiite militia bases near Baghdad. In line with policy, officials from Israel refused to confirm responsibility for the attacks.
Read more: Iran's allies in Iraq and Lebanon
Aramco 'game changer'
Israel's threat perception changed dramatically at the height of the Gulf standoff in September when a swarm of drones and low-flying cruise missiles hit Saudi Arabia's state-owned Aramco oil facilities and cut its production in half — an attack widely believed to have been carried out by Iran. But the attack was claimed by Iran-backed Houthi rebels in Yemen, and Iran has denied involvement.
"Aramco was a game changer in terms of balance of deterrence in the region," Vaez said, pointing out that Israeli defenses are calibrated for ballistic missiles rather than the low-flying cruise missiles used against Saudi Arabia.
Vaez said none of Israel's existing defenses would be able to prevent a "nightmare scenario" attack on chemical plants or nuclear facilities — "making parts of Israel uninhabitable for decades."
In the face of this "biggest risk," said Vaez, the "question for Israel is whether that means it should avoid the clash and let the threat grow over time or whether it should take the risk and try to nip it in the bud."
Broken nuclear deal
Netanyahu has long advocated taking that risk. In September, The New York Times reported that in 2012 Netanyahu was closer than ever to carrying out a unilateral strike on Iran that would have drawn a reluctant, diplomacy-oriented US into war. But, as Iran reestablishes its nuclear program, his allies might increasingly find his call for strikes on Iran persuasive.
Since Trump pulled out of the JCPOA, the United Kingdom, Germany and France have tried to bring other countries into the INSTEX trading body, which was designed to get around US sanctions, but they have almost entirely failed to stop companies from fleeing the Iranian market.
As a way to create leverage for itself, Iran has taken several successive steps that violate the terms of the nuclear deal. It has brought new facilities online, increased its stockpiles of nuclear material and enriched some of it to 4.5%.
Getting to that level of concentration takes more than 80% of the effort for producing weapons-grade uranium, according to the World Nuclear Association.
Vaez said Iran's aim was not to get a bomb but to "raise the cost on the US's maximum-pressure strategy and compel the remaining signatories to throw them a lifeline."
EU signatories to the JCPOA have held off from triggering a dispute mechanism that would see new UN sanctions and a possible end to not only the deal but also the Treaty on the Non-Proliferation of Nuclear Weapons. However, President Hassan Rouhani has signaled that Iran will take another step in violation of the deal in early January.
Differences in perception
The European Union's position is slowly aligning with that of the US, said Sanam Vakil, the head of the Iran Forum at Chatham House. Enrichment beyond 20% would see the deal collapse — a red line for Israel, Vakil said.
Protests this autumn in Lebanon and Iraq against Iran's regional influence and a short but bloody uprising at home could pressure the government into pursuing diplomatic negotiations, Vakil said.
"As news trickled out, we understood [the protests] were much more violent and threatening than we previously thought them to be," Vakil said. "This could alter Iran's calculations domestically and with regards to negotiations or potential for an escalation. Iran is backed into a corner right now, and it has few avenues that it can further pursue."
Officials in Washington also consider the protests a sign that economic pressure has worked, Vaez said. But, he added, Iranian officials are operating with increased self-confidence after successfully pushing back against the US across the region at little cost, attacking Aramco with no consequence and crushing protests in a matter of days.
Vaez said that those differences in perception raised a "major risk of the two sides remaining locked in the cycle of escalation" and "potentially ending up in a conflict that nobody wants but can easily spiral out of control."
Electoral wild cards
With elections looming in Iran, the US and Israel, the window for diplomacy is closing.
Both Netanyahu and Trump could benefit from a distraction. Netanyahu has been indicted on charges of fraud, bribery and breach of trust. Trump faces impeachment for abuse of power and obstruction of Congress. Iran, meanwhile, might see little reason for dealing with Trump with his foot potentially out the door, and, without concessions from the United States, Rouhani will lose support in parliament to the hard-liners.
Trump's reputation as the "Twitter tiger" also provides room for miscalculation in Iran, Vaez said. The president may stand to gain domestically by responding to a provocation.
"Beyond the first few months of next year, it will be almost impossible to de-escalate tensions," Vaez said.
Iran has less to lose after remaining faithful to a broken JCPOA brought no reprieve, and pushing back with its nuclear program didn't work. Tehran may also calculate that whatever they do, Trump won't respond.
"That combination of less to lose and less to fear is a very dangerous one," he said.