Benjamin Netanyahu, Israel’s prime minister, was one of the first foreign leaders to visit US President Donald Trump after his election in November and his inauguration in January for a simple reason — the US and Israel have one of the strongest military to military alliances in the world.

But why?

The US supports Israel in diplomatic and military matters not because of the strength of pro-Israel lobbies like the American Israeli Public Affairs Committee, or out of sympathy stemming from the events of World War II, but for practical reasons.

Michael Koplow, a Middle East analyst at the Israel Policy Forum, told Business Insider that the US’s alliance with Israel owes to two key factors — intelligence sharing and ideological unity.

Israel’s intelligence and insights into Middle Eastern affairs is “unparalleled” throughout the world and “benefits the US in all sorts of ways.” For decades, intelligence analysts have regarded Israel’s Unit 8200 as one of the most elite in the world. The unit functions similarly to the US National Security Agency, and the two work closely together.

In 2010, for example, the US and Israel collaborated on one of the most-sophisticated malware systems ever created, Stuxnet, to infiltrate Iran’s cyber infrastructure and slow progress towards nuclear weapons without firing a shot. In missile defence as well, US and Israel have worked together to field some of the most effective systems around.

Unlike other US allies in NATO and the Pacific, the US has no forward-based troops in Israel, which could serve as a “port of last resorts,” should the US ever need friendly territory to stage troops or equipment, according to Koplow.

But besides having perhaps the world’s greatest intelligence sharing partnership, the US and Israel see eye to eye on something fundamental to both states — democracy.

“Israel is the only liberal democracy in the Middle East,” said Koplow, who added that there are “many shared societal values between US and Israel.” Like the US, Israel has regular and open elections with peaceful transitions of power. In a region with failed and failing states Israel is “really an important ideological ally,” said Koplow.

The risks of the alliance

Like the US, or virtually any country on earth, Israel is not without its enemies. The United Nations has pushed back on Israel’s treatment of Palestinians and their support for Jewish settlements outside of Israel’s borders.

Specifically, Israel just pushed through legislation that retroactively legalizes about 4,000 settler homes built on privately-owned Palestinian land in a move that a UN spokesperson called a “contravention of international law.”

“If you’re a supporter of the Palestinian cause, it’s reasonable to ask why the US is supporting Israel,” said Koplow, adding that many in the US “take exception to the US funding Israel given the treatment of Palestinians.” Furthermore, US military aid and weapons have been used by the Israelis against Palestinians in their territory.

Others worry about the balance of the US’s aide to Israel. In 2015 more than half of the US’s foreign military aid went to Israel. That’s about $US3.1 billion dollars. Much of this money Israel spends on US defence projects in return.

According to Koplow, Israel’s treatment of the Palestinians have not gone unnoticed by its neighbours in the Middle East. “Historically, support for Israel obviously causes tension with allies in the region … there are people who question whether our support for Israel is worth the friction it causes with other US allies.”

But the US’s allies have learned to deal with Israel.

Saudi Arabia and other Gulf nations no longer protest the US-Israeli relationship as they did in the 1970s with the oil embargo, as the US now has many sources of oil and the price of crude oil has plummeted.

Iran, however, is not a US ally and remains a sworn enemy of Israel. Iran openly supports Hezbollah and Hamas, militant groups in the West Bank, Gaza, and Lebanon which wage war against Israel. Iran tests ballistic missiles with “Israel must be wiped off the face of the planet,” and launches naval vessels with slogans like “death to America.”

Public Domain
USS Liberty (AGTR-5) receives assistance from units of the Sixth Fleet, after she was attacked and seriously damaged by Israeli forces off the Sinai Peninsula on 8 June 1967. An SH-3 helicopter is near her bow.

Rifts in the alliance

Today the US and Israel find themselves at odds over issues such as the Jewish settlements in the West bank and Gaza or if Israel should pursue a one or two state solution to their borders, but in the past, confrontations have been much more substantial, and sometimes violent.

In 1967, Israel’s air force knowingly attacked the USS Liberty, a US Navy vessel in international waters in the Mediterranean.

The attack killed 34 virtually defenseless US sailors as Israeli planes and torpedo boats made multiple attacks.

Israel apologised for the attack, claimed it was a mistake, and compensated the US, but survivors of the attack maintain that it was deliberate.

In the 1980s, Jonathan Pollard, an American naval intelligence analyst passed classified information to the Israelis that the US had withheld despite a memorandum of understanding between the two nations that such intelligence should be shared. Pollard eventually pleaded guilty to one count of conspiracy to commit espionage and served 30 years in prison.

“The decision I made was based on fear and concern” for Israeli lives being endangered because the US wasn’t sharing information as they had agreed to, Pollard told Israeli TV. “Those were emotions that got the better of me,” he said.

So while the US alliance with Israel puts American diplomats in some tricky situations with the UN over human rights concerns and Iran, the alliance has survived sometimes extreme difficulties to massively benefit both parties while supporting a strong, liberal democracy in the Middle East.

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