As President Trump and Prime Minister Netanyahu get set to meet next week, the issue most likely to dominate the discussion will not be the Israeli-Palestinian conflict or even the Iran nuclear agreement, but Iran’s role in Syria.  This could potentially lead to some significant disagreements between the United States and Israel on how to tackle this challenge.  So lets try to examine the evolving positions on this issue, where the disagreements might come, and how the United States and Israel can work together in Syria to counter Iranian influence.

Israel has long raised alarm bells about Iran’s role in Syria.  However, rather than calling on the United States to overthrow the Assad regime or pursue grander strategies such as no fly zones or safe zones, Israel has for years opted instead to focus primarily on three more limited objectives.  First, prevent chemical weapons from getting loose in Syria and threatening Israel.  Second, prevent Iran’s proxies from establishing a foothold on the Golan Heights.  Third, stop the transfer of sophisticated weaponry from Damascus into Lebanon and Hezbollah.  Israel has been willing to take limited military action to achieve these objectives, including direct strikes on Syrian military facilities and convoys as well as support for moderate opposition forces on its border.  This approach has been pretty successful on two of its three objectives – keeping Iran off its border and keeping chemical weapons from falling into the wrong hands.  But the Israeli government never publicly or privately called for regime change in Syria and it never took steps to effectuate that outcome.

This approach stood in strong contrast to the approach of many of the Arab states and Turkey, who for years pushed the Obama administration to get more involved in Syria, both because of their hatred of Assad and their fear that Iran would exploit the situation.  Even the Obama administration went further publicly than Israel by calling on Assad to go.  But in the early years – when bolder efforts to arm the opposition or intervene more directly may have made more of a difference – the Obama administration stood on the sidelines.  This, in my view, was probably President Obama’s single greatest policy failure, and I advocated for the U.S. to intervene both when I was working on Capitol Hill and when I was out of government.  The president also infuriated and deeply frustrated many of our Arab partners, who viewed our failure to act in Syria as a terrible mistake.  But even though President Obama and Prime Minister Netanyahu deeply disagreed on Iran, Netanyahu never urged the United States to overthrow the Assad regime, including in his highly contentious speech to Congress.

Fast forward to today.  Russia intervened in 2015 and has fundamentally changed the dynamic on the ground.  Iran has invested deeply in Syria, building out a militia network that includes Hezbollah, Afghans, Pakistanis, and Iraqis all acting as a central part of the regime’s ground forces.  Most of western Syria – most notably Aleppo – has fallen to Assad, and displacing him at this point does not seem feasible.  The Arab states have given up on regime change; they simply want the war in Syria to be over, and have moved on to other challenges, such as Yemen.  The Trump administration has resigned itself to this reality and begun negotiating with Russia on deescalation zones that could tamp down the fighting and open space for the conflict to end.

But as acceptance of this new reality occurs, Israel finds itself increasingly isolated and alarmed.  Iran is consolidating its position in Syria and deepening its conventional military capabilities, even discussing the possibilities of a naval base.  It turns out the only way to truly keep Iran out of Syria is to keep Assad out of Syria.  But unfortunately, there is little support anymore in the United States, the Middle East, or across the globe for this approach.  And increasingly, it could lead to disagreements between the United States and Israel, such as the one we saw when Prime Minister Netanyahu objected to the agreement on a deescalation zone in southwest Syria for fear it would give Iran a toehold on the Golan.

So the question today for Israel and the United States is: what can they realistically do together to limit Iran’s influence in Syria?  The good news is that there are still some options. The bad news is that all of those options are limited.

First, the United States should essentially guarantee that Iranian forces remain off of Israel’s border. This is certainly the Trump administration’s intention with the deescalation zone agreement between the United States and Russia in the southwest.  The good news is that the forces that dominate this area are moderate opposition actors supported by the United States and Jordan, giving us plenty of leverage.  But the problem is that right now it is the Russians who are monitoring enforcement of the ceasefire, and there are still no written guarantees that Iran will be off the border.  The U.S. should make that point absolutely clear to Russia as a redline, and should even be willing to deploy a small number of forces to enforce any agreement and keep Iranian militias out, or – if necessary – support Israeli military actions in Syria that try to achieve this objective.

Second, the United States should to the extent possible prevent Iran from being able to freely move forces between Iraq and Syria by taking control of territory in eastern Syria. There has been a significant focus on the notion of a “land bridge” from Tehran to the Mediterranean, but trying to move forces 1,000 miles across highly precarious territory is of minimal value for Iran, especially given its alternatives via air.  Iran’s real objective is to hold as many key transportation routes as possible within Syria and Iraq so that it can more easily move its forces – including Hezbollah, other Shia militias, or the IRGC Qods Force – within and between these territories, giving itself maximum battlefield flexibility and diversified supply routes.  The U.S. should limit Iranian flexibility and control of these routes.  By maintaining forces at Al-Tanf in Syria, the U.S. has cut off Iranian use of the southern (and most direct) route from Baghdad to Damascus.  In the north, the United States should be able to use its close alliance with Syrian Kurds to prevent Iranian shipments of weapons.  The question will be in the center, at the border crossing between Anbar and Der-e-Zur province, which is currently held by ISIS.  If American-supported forces are able to retake this territory, they would cut off any options for Iran – though even if Iranian proxies hold it, it is highly inhospitable terrain for Shia militia groups. Nevertheless, this should remain a priority for the United States in the months ahead.

Finally, the United States should be willing to expand its support for Israeli action against Hezbollah in Lebanon, and set some clear redlines for Iran regarding its efforts to build out a military infrastructure in Syria.  American threats can have a deterrent factor, and limited joint military and intelligence actions can cause some damage to Iran’s efforts, although realistically they are unlikely to be game changers.

The sad reality is that the only way to truly keep Iran out of Syria was to keep Assad out of Syria.  The United States failed to act when there were many more options for doing so, and that was a great mistake.  But Israel also failed to recognize that this was the only true way to limit Iran’s position in Syria and chose not to push this point with the United States, instead opting for more limited objectives.  The United States and Israel now have to live with those decisions and limit the damage as best they can.