It’s not just Saudi Arabia that puts a high US price on diplomatic relations with Israel. So does Israel.

A confidante of Israeli Prime Minister Binyamin Netanyahu, strategic affairs minister Ron Dermer is in Washington this week for talks with senior officials, including President Joe Biden’s national security advisor, Jake Sullivan.

In a phone call last month, Mr. Netanyahu told Mr. Biden that he wanted a security treaty with the United States focused on deterring Iran as part of normalising relations between Israel and Saudi Arabia.

US and Israeli officials may not want to admit it, but there is little doubt that the Israeli demand complicates Mr. Biden’s already complex efforts to persuade the two Middle Eastern nations to formalise their substantial informal ties.

Saudi Arabia has put a steep price on establishing diplomatic relations that cater to its security and geopolitical interests.

Saudi Arabia demands security arrangements with the United States, US support for its peaceful nuclear programme, and unfettered access to sophisticated US weaponry. Saudi Arabia has also made Israeli moves to resolve its conflict with the Palestinians a pre-condition.

Like Israel, the kingdom wants a formalised security agreement, even if that accord may not target Iran as explicitly as Israel’s request does.

Saudi Arabia will likely be more circumspect following the China-mediated agreement in March to reestablish relations with Iran. Relations ruptured in 2016 when mobs stormed Saudi diplomatic missions in Iran in protest against the execution of a prominent Saudi Shiite cleric.

So far, from Saudi Arabia’s perspective, the agreement has only partially paid off.

To be sure, the agreement, alongside recent rapprochements between other Middle Eastern states, including Egypt, Turkey, Israel, Syria, and the United Arab Emirates, has dialled down regional tensions.

The kingdom and Iran have exchanged ministerial visits, reopened diplomatic missions, spoken about security and economic cooperation, and invited each other’s leaders to visit.

Iranian Foreign Minister Hossein Amir-Abdollahian visited Saudi Arabia this week for the first time since diplomatic relations resumed.

Most importantly, as seen in Riyadh, Iranian recent aggressive moves in Gulf waters target US and Israel-related vessels rather than Gulf state ships and exclude attacks on Saudi and Emirati oil and other infrastructure.

An informal agreement between the United States and Iran, involving a prisoner swap and a release of frozen Iranian funds, could lead to Iran refraining from attacking US shipping.

The deal does not signal a possible return to the 2015 international agreement that curbed Iran’s nuclear programme, even though Iran has reportedly slowed the pace at which it  accumulates near-weapons-grade enriched uranium and diluted some of its stockpiles.

However, Mr. Netanyahu has made clear that nothing short of the complete termination of Iran’s programme is good enough as far as he is concerned.

“Arrangements that do not dismantle Iran’s nuclear infrastructure do not stop its nuclear programme and will only provide it with funds that will go to terrorist elements sponsored by Iran,” Mr. Netanyahu’s office said.

The statement contrasts starkly with a US position articulated in March by Joint Chiefs of Staff chairman, Gen. Mark Milley. Mr. Milley told Congress the United States would not allow Iran to “have a fielded nuclear weapon.” The key word here is “fielded.”

Saudi Arabia and Israel may be closer than meets the eye when it comes to Iran, but they strike different tones. Moreover, Israel is less inclined to deal with the current Iranian regime than Saudi Arabia is.

Addressing a closed meeting in Europe with Middle East experts, a senior Saudi official recently said it was the kingdom’s “hope” to resolve issues with Iran but cautioned that “it is too simple to think in that way—and also dangerous, because if you don’t see results you will think that de-escalation is in vain or has no results.”

He likened Saudi Iranian relations to Europe’s relations with Russia. Europe has “diplomatic relations with Russia, but you’re at war with Russia,” the official said.

The official conceded that prospects for economic cooperation with Iran remained limited without reviving the Iranian nuclear deal because of US sanctions.

Phrased differently, Saudi Iranian relations depend as much on policies crafted in Riyadh and Tehran as on policies pursued in Washington.

All this casts a different light on Mr. Netanyahu’s demand for an Iran-focussed security agreement with the United States.

Mr. Netanyahu has made establishing diplomatic relations with Saudi Arabia a crown jewel of his foreign policy.

To achieve that, Israel has acquiesced in Saudi Arabia enriching uranium for research purposes as part of a US-Saudi deal.

Mr. Netanyahu has also indicated he would be willing to gesture to Palestinians if a normalisation deal with Saudi Arabia depended on it. He suggested he would not let ultra-conservative religious and ultranationalist coalition members block an agreement.

It’s not clear that the prime minister could make gestures that would be minimally acceptable to the Saudis and avoid breaking up his coalition, the most hardline in Israeli history.

This month’s appointment of Saudi Arabia’s first ambassador to the Palestinians suggested the gap Mr. Netanyahu would have to bridge.

Israeli Foreign Minister Eli Cohen did not object to the move but asserted Israel would not permit the opening of diplomatic representations for the Palestinians in Jerusalem.

Israel views united Jerusalem as its capital, while the Palestinians see the east of the city, captured by Israel during the 1967 Middle East war, as the capital of a future Palestinian state.

As the custodian of Islam’s holiest cities, Mecca and Medina, Saudi Arabia would be hard-pressed to make concessions on Jerusalem, the faith’s third holiest city.

As a result, the question is what Mr. Netanyahu wants to achieve with his demand for an anti-Iran security deal with the United States.

Certainly, the deal would ensure Israel’s seat at the table and bolster Israel’s position vis a vis Iran.

Mr. Netanyahu may also want to complicate US-Saudi talks about security arrangements in the belief that without a solid agreement with the United States, the kingdom would have a greater interest in formalising relations with Israel sooner than later.

Either way, Israel remains a player with the potential to be disruptive rather than constructive, depending on how Mr. Netanyahu defines Israel and his political interests.