Since the collapse of the Soviet Union and the establishment of diplomatic relations between Russia and Israel, Moscow has on a number of occasions cancelled the delivery of advanced weapons systems to Syria and a number of other potential Middle Eastern clients at the request of Tel Aviv. These included MiG-31 interceptors, advanced combat platforms which Damascus required to match the Israeli F-15 Eagles provided by the United States, as well as modern variants of the S-300 surface to air missile system to upgrade the Syrian air defence network - an asymmetric measure to protect the country's airspace from strikes by Israel's far superior air force. While during the Cold War Syria was provided with some of the most capable Soviet weapons available, including its most capable fighters and interceptors, the MiG-23 and MiG-25, as well as T-72 battle tanks and other cutting edge weapons systems which Damascus was among the first in the world to deploy, this came to an end with the USSR's fall.
The Syrian Air Defence Force had been the first in the world to deploy the S-200 air defence system outside the USSR itself, a platform it continues to field until today and has used to great effect against both U.S. and Israeli fighters. The platforms were notably delivered in the immediate aftermath of a massive Israeli Air Force operation, Mole Cricket 2, which saw newly delivered F-15 fighters spearhead an assault on the country's older S-125 air defence batteries and destroy several. With neighbouring Egypt having shared the details of the S-125's capabilities with the United States, and with this information widely suspected to have been passed onto the Israeli Air Force, the missile system proved incapable of deterring attacks by modern U.S. built fighters without undergoing considerable upgrades. Damascus was as a result within weeks provided by the USSR with more capable systems, the S-200, to deter further attacks. These platforms were notably delivered at significant discounts and paid for with loans which were in many cases later forgiven - allowing Syria to defend itself largely at the Soviet Union's expense.
Today the situation has changed profoundly, and Damascus' relationship with Moscow is far from what it was in the Soviet era. While Syria has suffered regular attacks by Israeli fighters, it has been forced to rely on its older air defence platforms, upgraded with North Korean assistance, to defend itself. It has done so by targeting Israel's air launched missiles at close ranges - lacking the advanced long ranged capabilities to target the fighters themselves which regularly strike from beyond the Syrian airspace. With Russia failing to provide Syria with combat aircraft or modern air defence platforms required, Syria's position remains far weaker than it could be. Russia indicated that it was reconsidering providing Damascus with the S-300 following a massive missile strikes carried out jointly by the United States, France and Britain in April 2018, which would have given Syrian air defence forces coverage extending over Tel Aviv and Ben Gurion airport itself - seriously complicating Israeli attacks. The delivery was widely reportedly cancelled however following a visit by Israeli Prime Minister Benjamin Netanyahu to Moscow in early May, where he met with Russian President Putin and attended Russia's Victory Day military parade. This came as the Israel Air Force launched numerous air strikes against Syrian targets on an unprecedented scale, with many strikes taking place while the Prime Minister was in Russia.
The Kremlin for its part has done little to protect its oldest regional ally from these attacks. This is a far cry for the policy of the Soviet Union, and ultimately has done a great deal to undermine Syrian security. While Moscow has drawn a red line in the past at a Western intervention to topple the Syrian government as per Iraq and Libya, which would weaken Russia's regional standing considerably, the Kremlin appears far more willing to tolerate attacks on Damascus by neighbouring Israel. Though Syrian-Rusian military cooperation is set to remain strong, Damascus may well begin to consider looking elsewhere for combat aircraft and longer ranged anti aircraft missile systems in light of Moscow's unwillingness to provide for its defence needs - increasingly a necessity in light of the growing scale and frequency of the Israeli attacks.