One month after the WSJ reported that Israel had been secretly funding the Syrian rebel opposition to Assad's regime for years in hopes of keeping the Syrian political situation unstable and preventing the Syrian - and Iranian - regime's military from becoming a substantial threat, overnight Israel Prime Minister Benjamin Netanyahu told reporters after his meeting with French President Emmanuel Macron on Sunday that Israel opposes the cease-fire agreement in southern Syria that the United States and Russia reached "because it perpetuates the Iranian presence in the country."

Quoted by Haaretz, a senior Israeli official said Israel "is aware of Iranian intentions to substantially expand its presence in Syria", and added that Iran is not only interested in sending advisers to Syria but also in dispatching extensive military forces including the establishment of an airbase for Iranian aircraft and a naval base. "This already changes the picture in the region from what it has been up to now," the official said.

Which considering that most if not all of Syria's victories in the ongoing parallel proxy wars with both ISIS and the various "moderate" and not so "moderate" rebel groups were courtesy of Iran and specifically the IRGC, is to be expected. Still, by openly voicing his opposition to one of the most significant moves the United States and Russia have made in Syria in recent months, Netanyahu made public a major disagreement between Israel and the two great powers that had until now been kept under wraps and expressed only through quiet diplomatic channels. Netanyahu said he had discussed the cease-fire deal with U.S. Secretary of State Rex Tillerson by phone Sunday night.

As a reminder, Donald Trump and Vladimir Putin agreed on the cease-fire on the sidelines of the G20 summit in Hamburg last week. In a tweet published shortly after the truce came into effect last week, Trump tweeted: "We negotiated a ceasefire in parts of Syria which will save lives. Now it is time to move forward in working constructively with Russia!"

One week later, however, the truce faces the daunting hurdle of Trump's biggest ally in the region openly opposing what may be the US president's biggest diplomatic achievement to date.

In addition to the ceasefire, the U.S.-Russian deal included establishing de-escalation zones, otherwise known as safe zones, along Syria’s borders with both Jordan and Israel.

According to Haaretz, over the past month, Israel had held talks on this agreement with senior American officials, including Brett McGurk, America’s special envoy for the battle against ISIS, and Michael Ratney, the special envoy for Syria, both of whom visited Israel several times. During these talks, Israel presented a list of demands and voiced several reservations about the emerging agreement. Among others, Israel said that the de-escalation zones must keep Iran, Hezbollah and other Shi’ite militias away from the Israeli and Jordanian borders and must not enable Iran to consolidate its presence in Syria. Israel also told the Americans it objected to having Russian troops policing the cease-fire in the safe zones near its border.

Curiously, Haaretz notes that Israel was a vocal member of the negotiations that took place over the Syrian ceasefire, and in the days before the United States and Russia announced the cease-fire deal for southern Syria, Netanyahu spoke by telephone with both Tillerson and Russian President Vladimir Putin to reiterate Israel’s positions on the agreement. At the start of the cabinet meeting on July 9, Netanyahu said that both Putin and Tillerson had told him they understand Israel’s position and will take its requirements into account. However, when Jerusalem obtained the text of the deal, it discovered to its surprise that the Americans and Russians "had ignored Israel’s positions almost completely."

“The agreement as it is now is very bad” one senior Israeli official said. “It doesn't take almost any of Israel's security interests and it creates a disturbing reality in southern Syria. The agreement doesn’t include a single explicit word about Iran, Hezbollah or the Shi’ite militias in Syria.”

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What Israel's opposition to the Syrian ceasefire means, is unclear. While the deal is surprisingly still holding one week after its implementation, perhaps the longest period of time a Syrian ceasefire has held for the duration of the country's 6-year war, with Israel voicing its non-compliance, it is possible that it will be none other than Netanyahu who breaches the terms of the agreement should Israel feel "threatened" by Hezbollah, or other Shi'ite militias.

Whether that will force Trump to choose between Putin and Netanyahu is open to debate. However, it likely means that now that the Syrian war is slowly fading away, the region's longest-simmering, dominant conflict, that between Iran and Israel, is about to retake its rightful place.