Iran has, experts say, “the largest and most diverse ballistic missile arsenal in the Middle East.” Developed with Libyan and North Korean aid, the Iranian missile program now boasts a range of weapons that can reach Israel and many other targets around the region.

(This first appeared in 2014). 

Israel has its hands full at the moment in Gaza. But Gaza’s rockets aren’t the only thing that keep Israeli strategists up at night. 

Last week, the nuclear talks between Iran and the P5+1 were extended into late November. A deal is still a very real possibility. But failure is, too. There’s broad agreement across the Israeli political spectrum that letting Iran get the bomb is an unacceptable risk. Many in the Israeli national-security establishment, particularly around Prime Minister Benjamin Netanyahu, have entertained the notion of an Israeli strike on Iran’s nuclear facilities if diplomacy fails and Iran makes a move toward the bomb. Iran would surely retaliate.Iran has a problem, though. If you’ve looked at a map lately, the Islamic Republic doesn’t share a border with the Jewish state. They’re more than 550 miles apart at their closest, and the two countries’ cores are nearly one thousand miles apart. That’s a big challenge for Israel, whose powerful air force would have to fly to the limits of its range just to reach Iran’s nuclear facilities. But it’s a bigger challenge for Iran, whose air force, held back by decades of sanctions, is far too feeble to break into Israel’s well-defended airspace.

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Iran’s response to these challenges has been to develop a range of tools, many of them underhanded, that would allow it to hit Israel back. But not all weapons are created equal. Prior lists in our “Five Weapons” series have tried to rank weapons systems not just by how advanced they are or how widely they were used. After all, an advanced weapon might be too expensive and draw resources away from other systems, reducing overall military effectiveness (see Germany in the Second World War). A ubiquitous system might not be very good, also cutting its utility. And a weapon that doesn’t have a good crew behind it might as well not be good. But so many of Iran’s tools are highly asymmetric and highly secretive. Their impact on the strategic balance is the only criterion we can rely on. So what can Iran count on to mitigate the risk of an Israeli strike—and to hurt Israel if it does attack?

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5. Iran’s Palestinian Proxies

Iran always tries to take the toughest line in the Muslim world in its support for Palestine. Tehran is a key supporter of rejectionist elements that refuse to recognize Israel and are ready to take up arms against it. Iran’s traditional best buddy in this has been Hamas. Hamas’ control of the Gaza Strip and its growing rocket capabilities—they’ve shown they can hit Tel Aviv—make it a difficult foe. But events in Syria seriously damaged Iran’s relationship with Hamas—the Sunni Palestinian group didn’t like watching Iran back the Alawite Bashar al Assad to the hilt as he brutalized the heavily Sunni opposition. Iran cut off the tens of millions of aid it sends to Hamas each month—and Hamas answered by announcing that it would not become involved in a conflict between Iran and Israel. But things turned south fast for Hamas when Mohamed Morsi’s government was overthrown in Egypt. Hamas is aligned with the Muslim Brotherhood, so Morsi was a kindred spirit. The virulently anti-Brotherhood Sisi government, not so much. Egypt’s taking a much harder line toward Hamas now, including by cracking down on its lucrative networks of smuggling tunnels. This pushed Hamas back into Iran’s arms.

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But how much of a hammering would Hamas be willing to take on Iran’s behalf? Not so clear. That’s why Iran has sought ties with Palestinian movements more extreme than Hamas, chiefly the Palestinian Islamic Jihad (PIJ). PIJ has rockets and fighters and a long history with Iran. It’ll be a more reliable ally than Hamas. Yet with both militias, a question remains: How much of an impact can they have? The current conflict has shown that Israel’s Iron Dome missile-defense system can catch most of the Palestinians’ rockets.

Of course, Israel still isn’t safe in these conditions, and has been drawn into ground operations. That’s what Iran wants in the event of a conflict. Yet the Iron Dome gives Israel the ability to juggle priorities more efficiently. If it’s also facing, say, a major bombardment from Hezbollah in the north, and feels it needs to go in on the ground in both Lebanon and Gaza, the Iron Dome might allow Israel to fight one ground war at a time, leaving the Palestinians on the back burner while it goes after Hezbollah first.

The unknown here is Iran’s capabilities to cause trouble in the West Bank. Israel’s extensive military and settler presence in the West Bank presents a ripe target, and the West Bank is closer to Israel’s core, too. Nothing massive is likely, but Iran would hope to draw at least some blood and divert at least some Israeli effort there.

Editor’s Note: Please see previous works from our “Weapons of War” series including: Five NATO Weapons of War Russia Should Fear, Five Russian Weapons of War NATO Should Fear, Five Chinese Weapons of War America Should Fear, Five American Weapons of War China Should Fear, Five Japanese Weapons of War China Should Fear, Five Best Weapons of War from the Soviet Union and Five Taiwanese Weapons of War China Should Fear.

4. Terrorists and Spies

Iran has extensive networks of spies, smugglers, money launderers and worse around the globe—including in places you wouldn’t expect, like South America and Canada. One of the more odious elements of Iran’s foreign policy—well, before it was a major backer of Bashar al Assad’s urban demolition, torture  and asphyxiation campaign in Syria and before one of Tehran’s proxies in Iraq was committing massacres—was its willingness to use those networks to attack Israeli diplomats and, worse, to treat non-Israeli Jews as proxy targets when it didn’t feel like going after Israelis. This was the case in Argentina, when friends of the Islamic Republic bombed Israel’s embassy (1992, twenty-nine dead) and a Jewish community center (1994, eighty-five dead). Similar attacks—fortunately with no deaths—followed eight days later in London. And these were not isolated incidents. After Israel was apparently involved in the assassination of several Iranian nuclear scientists, Israeli diplomats were targeted in Tbilisi, Georgia and New Delhi, India in February 2012, with the wife of Israel’s military attache to India being seriously injured. A similar attack in Thailand failed, apparently due to the incompetence of the attackers; that July, a suicide attack by apparent Hezbollah operatives on a busload of Israeli tourists in Bulgaria killed six innocent people. And alleged Iranian plots have been uncovered around the world in recent years, including (most alarmingly) a 2011 plot to assassinate the Saudi Arabian ambassador to the United States in a swank Washington, D.C. restaurant—with the convicted terrorist saying “no big deal” when he was told that the attack could have caused 100 or even 150 casualties.

Iran’s operatives abroad aren’t always the most effective or the hardest to detect, and Israel seems particularly effective at stopping Iranian agents from operating inside its own borders. Yet, as the saying about aerial warfare used to go, the bomber will always get through. Lives would be lost around the world in the wake of an attack on Iran. Attacks might occur inside the United States, and would be at Tehran’s discretion in Europe, too. The world’s security services would likely appreciate as much warning as Israel could give them that an airstrike was coming, as that would give them the chance to round up as many Iranian agents within their country as they could find. But they’d be unlikely to get everyone.

3. Ballistic Missiles

Iran has, experts say, “the largest and most diverse ballistic missile arsenal in the Middle East.” Developed with Libyan and North Korean aid, the Iranian missile program now boasts a range of weapons that can reach Israel and many other targets around the region. Iran’s even dabbled with missiles that could hit Western Europe. Iran also has shorter-range missiles that it can deploy against its unfriendly neighbors to the south—particularly Saudi Arabia—and might consider taking potshots at American troops in Afghanistan or American allies further afield, like Jordan. A comprehensive study of a possible Iranian campaign against Saudi oil facilities suggest it wouldn’t be terribly effective. A potshot at the Israeli nuclear facility in Dimona—pulling a page from Saddam Hussein’s playbook—would also be unlikely to achieve meaningful results. But as a weapon of terror, missiles are more useful. A city—like Tel Aviv, for example—is much easier to hit than a reactor core or a refinery tower. Iranian ballistic missiles would be carrying heftier warheads than the ones Hamas is lobbing these days. The Iron Dome system wouldn’t help against big, fast ballistic missiles, and Israel’s Arrow anti-ballistic-missile system hasn’t been put to the test like Iron Dome has. Israeli cities might be tense places under such a bombardment. The real question, however, would be the accuracy and reliability of the missiles and the sustainability of the campaign. If the missiles aren’t finding their targets or Iran doesn’t have many to fire, Israel probably won’t come out of that exchange feeling like a loser.