Like rivers, wars surge and recede; like oceans they move in tides. Early this month, the tide of Syria's civil war appeared to turn sharply in favor of the rebels fighting President Bashar al-Assad when they managed to break the regime's siege of the strategically vital city of Aleppo.



It was a serious setback for Assad's forces, a loose coalition consisting of Hizballah, Iran's Islamic Revolutionary Guards Corps (IRGC), Iraqi Shi'ite militias, potentially more than 2,500 Russian private military contractors,

Russian soldiers, the remnants of the Syrian Army, and Kurdish splinter groups. Since then, the Russian air-powered fightback has begun.



Much of the recent media attention on Syria has fallen on Russia's entry last year into the war to help prop up Assad. Its air strikes have been devastating -- especially to Syria's beleaguered civilians.

Russian President Vladimir Putin wants to secure Russia's naval facility at Tartus, which will enable him to continue to project power in the Middle East. It also provides yet one more imperial adventure to distract his people from the contracting economy and increasingly lower standards of living they are now facing. And of course, he gets to thumb his nose at U.S. President Barack Obama, who has repeatedly stated that Assad must go.

Iran Spends 'Billions' On Assad

The fear of a revanchist Russia, threatening European stability with its interference in Ukraine and now threatening Middle East stability with its meddling in Syria, has transfixed observers. Turkey's recent foray into the conflict, on August 24, when its tanks and soldiers, backed by U.S. coalition air strikes, crossed the border to attack positions held by the militant group Islamic State (IS) near Jarablus, has only broadened -- and complicated -- the spectacle.

But largely lost in all of this has been the role of Iran, which has supported Assad since almost the moment that his brutal crackdown on demonstrators turned mass protest into a civil war. The Syrian military, especially its air force, was always more of an arena for politicking than an effective fighting force. Without Iran -- and specifically the IRGC, led by the supremely gifted military strategist Qassem Soleimani -- there would be no Assad for Russia to prop up.



Just days ago the National Council of Resistance of Iran (NCRI), an exiled Iranian opposition group, presented a dossier to MailOnline, which claimed that, as well as running Iranian operations in Syria from a secret HQ in Damascus known as "the Glasshouse," there are, in fact, 60,000 fighters under Iranian command in Syria -- far more than the 16,000 previously thought. It also asserted that Iran has spent "billions" -- possibly as much as $100 billion -- on supporting Assad since 2011.

Regional Outsider



Given its hostility to the Islamic republic, the NCRI has most likely inflated these figures, which, the MailOnline article concedes, have not been independently verified but have been deemed "credible" by "intelligence experts." Matthew McInnis and Paul Bucala, analysts from AEI's Critical Threats team, told RFE/RL that those numbers are high. They estimate that at any given point in time, between 13,000 and 15,000 Iranian proxies -- including fighters from Hizballah and Shi'ite militias from Iraq, Afghanistan, and Pakistan -- are overseen by approximately 3,000 Iranian military officers and other personnel in Syria. "These numbers are not static and fluctuate based on rotational cycles and changing military requirements," McInnis noted. AEI estimates that beyond this there are at least 100,000 fighters who make up the Syrian National Defense Force (NDF), which the IRGC and their paramilitary Basij force have helped to establish to prop up the Assad government.



What is not in doubt is that Iran has -- at a time when sanctions (since lifted following the deal struck last year to curb Iran's nuclear program) have bitten deep into its economy -- invested precious resources into a quagmire that it cannot afford. Its economy is in disarray, and even with the return of frozen assets and the possibility of increased global trade it is struggling with a host of serious domestic problems -- some of which, particularly the youth of its population and the state's inability to provide adequate employment for them, may yet prove existential.



The question is why? And the answer is integral to understanding Syria's civil war.



Iran is, like Israel, a regional outsider: a Shi'ite, Persian state in a predominantly Sunni Arab Middle East -- something it discovered to its cost when almost all the Arab states lined up behind Iraq during the 1980-1988 Iran-Iraq War. Syria was an exception. The two countries are long-standing allies.



But it is more than that; Russia is not the only revanchist nation in great power politics today. Iran, increasingly guided more by the concerns of the IRGC than the clerics of the holy city of Qom, now seeks to dominate the Middle East. And for that Syria is vital. As Jonathan Spyer, the director of the Rubin Center at the IDC Herzliya, observes: "Iran wants to build a contiguous line of Iran-aligned states between the Iraq-Iran border and the sea. Syria forms an essential component in that. Syria is also essential for the maintenance of supply lines from Iran to its main proxy organization, the Lebanese Hizballah. It is Hizballah which gives Iran its physical connection to the struggle against Israel, a struggle to which Iran is committed both for pragmatic and ideological reasons."

'Assadistan'



With its traditional adversary, Iraq, now to all intents and purposes a failed state under huge Iranian influence, and "the great Satan" -- the United States, as it is known by some of Iran's hard-line conservatives -- seemingly determined to pivot away from Saudi Arabia toward Tehran, the geopolitical map has re-formed almost perfectly in its favor.



But maintaining this status quo is largely dependent on keeping Assad in power. As long as the supply routes to Hizballah remain open it can continue to harass and pressure Israel, Iran's only regional rival of any real power. More than this, if Assad falls he will almost certainly be replaced with a Sunni regime utterly hostile to Iran, both for sectarian reasons (since Sunnis make up more than 70 percent of the country's prewar population and because its likely constituents will have spent years being killed by Iran and its proxies.

With Russian air power now in the fight this scenario is unlikely unless, as Spyer further observes, there is an opposing "commitment of Western air power to aggressively advance the rebels' cause." This is something he rightly assesses "almost certainly will not happen."



At the same time, Assad remains too weak to reconquer most of the regions in Syria he has lost.The most likely scenario is a truncated "Assadistan" that allows Iran to keep both its supply lines to Hizballah and the contiguity of allied states. And Russia naturally gets to keep its air base.



The losers are, once again, the Syrian people. Realpolitik in the Middle East is a dirty and nasty business, and Iran is its master practitioner.