The relationship between Israel and Iran is highly complex. The two states cooperated behind the scenes well into the 1980s, but today, the enmity runs deep.
If Israeli President Shimon Peres were to be asked whether Iran can be trusted, he would certainly answer "No."
"Iran is the center of world terror in our time," Peres warned the World Economic Forum in Davos in January. He's convinced that Tehran continues to support the Shiite Hezbollah militia in Lebanon with weapons, and that Iran is trying to develop nuclear arms, despite repeated denials by Iranian President Hassan Rouhani. For years, Jerusalem has more or less openly speculated about the possibility of a pre-emptive military strike on Iranian nuclear facilities.
Speculation was particularly rife during the presidency of Mahmud Ahmadinejad, who routinely ranted against Israel, challenged the Holocaust and condemned the Israeli occupation of Palestinian territories. His successor Rouhani has taken a more tempered approach: he also doesn't recognize the existence of the state of Israel, but he has dissociated himself from his predecessor's anti-Israel comments.
Nevertheless, the relationship between the two countries is defined by deep mistrust. This was not always the case.
Israelwas founded on May 14, 1948 - and found itself immediately at war with its Arab neighbors.
The Israelis managed to thwart the Arab attack, but the Palestine War showed Israel's founding father David Ben Gurion quite clearly the hostile surroundings in which the young state would have to hold its ground. He developed a so-called "alliance of the periphery," a foreign policy strategy that called for Israel to form alliances with non-Arab states and forces in the region, including Turkey, Lebanese Christians - and Iran.
In the early 1950s, Tehran, too, was suspicious about growing Arab nationalism - in particular after 1953, when Iran developed into a dictatorship strongly influenced by the US.
Tehran regarded Israel, which was also supported by Washington, as a welcome political counterbalance to its Arab neighbors. "The two countries had an excellent relationship," says Henner Fürtig from the Hamburg-based GIGA-Institute.
Israeltrained agricultural experts, supplied technical know-how and helped build and train the Persian armed forces - in return for crude oil, a resource urgently needed in economically ambitious Israel.
"In the late 1970s, Iran covered 80 percent of Israel's oil requirements," says Fürtig. "It was an existential relationship which was developed between the two states."
The 1979 Islamic Revolution in Iran put an abrupt end to that cooperation.
The new regime's spiritual leader, Ayatollah Khomeini, harshly criticized Israel for the occupation of the Palestinian territories. As soon as he had assumed power, he cancelled all agreements with Israel. When Israel intervened in the Lebanese civil war and marched into southern Lebanon in 1982, Khomeini sent Iran's revolutionary guards to Beirut to support the local Shiite militia. To this very day, the militant Hezbollah group that emerged back then is regarded as the long arm of Tehran in Lebanon.
There were increasingly public tensions between Iran and Israel, but at the same time, cooperation was secretly revived, triggered by the start of the Iran-Iraq war in September 1980.
Unimpressed by the revolution in Tehran, almost the entire western world supported Iraq, which had been armed to the hilt by the United States. Israel, on the other hand, regarded Saddam Hussein's regime as the greater threat - and sided with Khomeini.
According to a study conducted by the Tel Aviv Institute for National Security Studies (INSS), Israel supplied Iran with arms totaling $500 million (365 million euros) in the first three years of the war.
According to Fürtig, "Things were not looking good for Iran in the war with Iraq, partly because 90 percent of Iran's armaments had been acquired in the US during the Shah era." Those supplies were running out: "Iran was desperate for new suppliers prepared to provide US weaponry." Israel's offer was just what Iran needed.
Ayatollah Khomeini returned the favor when rumors started that Iraq was working on a nuclear bomb - a threat neither Jerusalem nor Tehran could accept. Iran's intelligence agency passed on valuable information to the Israeli air force, which bombed Iraq's Osirak nuclear reactor in 1981, setting back the suspected Iraqi nuclear program by years.
Such secret cooperation was highly sensitivem, says Fürtig, "and both sides tried to keep it under wraps. Neither Iran nor Israel wanted this to become public knowledge."
In November 1986, the Iran-Contra affair hit the United States: senior administration officials had secretly sold thousands of anti-tank and anti-aircraft missiles to Tehran and used proceeds from the weapons sales to fund rightwing Contra rebels in Nicaragua. Israel was significantly involved in the transactions.
The final break
Operation Desert Storm: Coalition forces led by the US marched into Iraq
In the wake of that scandal and the end of the Iran-Iraq war in 1988, ties between Israel and Iran were finally severed. Iraq, the common enemy, was weakened, and eventually more or less neutralized by the US-led Operation Desert Storm three years later.
Iranno longer had a reason to maintain its cooperation with Israel. In addition, Tehran began to focus on the Palestinian question. Iran habitually takes the Palestinian issue out of an Arab context and moves it into an Islamic context, Fürtig says: "By pulling the issue into the spotlight for all Muslims, and not just Arabs, Iran hopes to be awarded leadership competence - something Tehran doesn't want to relinquish."
Trita Parsi, President of the National Iranian American Council, says rivalry between two nations is by no means unusual, but "the problem with Israel and Iran is that their rivalry has taken on existential dimensions."
Iranprophesizes that the state of Israel will disappear, while Israel denies Iran the right to nuclear technology and actively participates in efforts to change the regime in Tehran. In such circumstances, says Fürtig, "an real substantial improvement in Iranian-Israeli relations is not to be expected any time soon."