Syrian crisis has weakened Hezbollah but passage of Iran deal would both embolden them and give them fresh resources

In a bid to prop up its valued allies in Syria, Iran has dispatched 6,000 to 8,000 Hezbollah fighters to fend off the Sunni militants seeking to topple the Bashar al-Assad regime. The war has taken its toll on Hezbollah, as body bags draped in the group's yellow flags continue to stream back from the front. An estimated 1,000 Hezbollahis have fallen since the group first began fighting there in 2013.

The Iran deal may soon give Hezbollah an exit strategy. Tehran is set to receive upwards of $100-$150 billion in cash (frozen funds plus funds released from escrow accounts holding oil proceeds that were only to be spent on approved foreign goods). Even more is coming to Iran in the form of increased oil, petrochemical, auto and gold revenues. The Assad regime could become a major beneficiary. This means that the regime could soon have more cash to pay its fighters and to buy more weapons to target the Sunni rebels waging war against it.

In that event, Hezbollah's services may no longer be in demand and the group could redeploy its troops fighting in Syria. How long that takes depends on how quickly Iranian cash and weapons help the Assad regime consolidate. But once its fighters are safely home, Hezbollah will soon benefit from the same Iranian sanctions relief windfall. As Iran's most important non-state proxy, Hezbollah stands to gain considerably -- from advanced weaponry to cash and training.

But even without a withdrawal from Syria, Hezbollah's battle-hardened fighters may not be content with quiet on their southern front. The group's rhetoric certainly has not mellowed; Hezbollah has been bruising for a fight with Israel since the guns fell silent from the last encounter in 2006. More importantly, Hezbollah views the nuclear deal (like the rest of the region) as a sign that its patron Iran is a burgeoning regional power, and that the military advantage is shifting away from Israel in the Middle East. It may not take long before the first provocation on the border.