This shift is partially a response to success on the field. ISIS is in retreat, and expected to lose its strongholds in Mosul (in Iraq) and Raqqa (in Syria). Thus, the various factions fighting ISIS have no reason to form the alliance that Trump hinted at. Instead, they are already preparing for a post-ISIS world by securing as much territory as they can. For Iran in particular, the end of ISIS would be their biggest unexpected bounty since the early days of the George W. Bush administration, when the U.S. obligingly removed Saddam Hussein and the Taliban from power in Iraq and Afghanistan, respectively. With ISIS out of the picture, Iran would have an unbroken swath of allies from Iraq to Syria to Lebanon—a land bridge to Israel’s border.

“As ISIS disappears off the map,” Ilan Goldenberg, a former state department official, told to the Guardian, “this tolerance that Shia Iranian-supported groups and American-supported groups have shown for each other—there is a danger that will go away. You can see it all going haywire pretty quickly.”

Goldenberg’s warning should be heeded. Clinton’s policies were controversial but at least sprang from a coherent foreign policy worldview which could be debated. Trump might be following Clinton’s policies in broad outline but with little thought to consequences. He appears to be responding to unfolding events in an ad-hoc way, rather than being guided by a broader strategy. This “incremental escalation,” according to national security expert and former Obama adviser Colin Kahl, could quickly escalate because of the “asymmetry of stakes.”

<THREAD> The cult of credibility is as popular in DC as it is dangerous. Watch Syria. The risk of sliding into a big war is rising. 1/ — Colin Kahl (@ColinKahl) June 19, 2017

Will cooler heads prevail in Trumpland or will the cult of credibility drag us deeper into the Syrian mess? 19/19 — Colin Kahl (@ColinKahl) June 19, 2017

Kahl notes that despite Trump’s more aggressive stance in Syria, the Assad regime, Russia, and Iran “haven’t backed down. They keep pushing, probing, testing, countering. They haven’t been cowed & deterred.” That’s because, whereas “the interests for the U.S. are important,” they are “vital” for the “Axis of Assad.” For Iran, the conflict is a chance to prop up a key ally in its broader regional struggle against Saudi Arabia. For Russia, propping up Assad would be a victory for their policy of national sovereignty versus America’s preference for regime change. For Assad, as Kahl says, the interests are “existential”—and not just for his government. If his regime falls, he may well end up like Hussein.



So the “Axis of Assad” won’t back down. Will Trump? Kahl seems pessimistic. If the axis retaliates over these recent provocations, the hawks in Trump’s National Security Council “will argue U.S. credibility has now been engaged, so we have to keep punching.” In effect, Trump is playing a game of chicken with foes that cannot afford to surrender, and the president might refuse to back down out of fear of losing face.