Chief Pentagon Spokeswoman Dana White released a statement  earlier this month announcing that President Trump had authorized the Defense Department to “equip Kurdish elements of the Syrian Democratic Forces (SDF) as necessary to ensure a clear victory over ISIS” in Raqqa. This week the group began to take delivery of arms shipments from U.S. forces in the region. Neither White nor the president has addressed how this action fits into U.S. grand strategy, how the White House plans to navigate the acute sensitivities of U.S. relations with NATO ally Turkey—which considers the SDF a terror group—or what the administration seeks as an end state once ISIS is driven out. This lack of concern over such major elements of a campaign plan continues a troubling lack of strategic understanding at the national level.
The announcements give the impression—intentionally, no doubt—that the desire to arm the Kurds is a relatively simple matter of supporting the most effective fighting force in Syria that can drive ISIS from their self-proclaimed capital of Raqqa. The unstated assumption is that militarily defeating ISIS in Raqqa may spell the end of the Islamic State, and U.S. national security would therefore be safeguarded. In all probability, the outcome of that battle, while satisfying, will not substantially improve U.S. national security. The fight itself, however counterintuitive it seems, may degrade U.S. security.
The push to destroy ISIS in Raqqa is understandable. President Trump made the defeat of ISIS a major campaign pledge, and he is intent on keeping that promise. But the higher level strategic objective needs to be safeguarding the American homeland using the most effective means possible. On the surface, going after ISIS wherever they are would seem a good thing. But the approach chosen to battle ISIS is critical, as not every tactic leads to a positive strategic outcome. Supporting the Kurds in Syria has serious second- and third-order effects, some of which could have a negative impact on U.S. security.
There is little doubt the Kurdish fighters in the SDF, called the People’s Protection Units (or YPG in their Kurdish rendering), are the most effective of virtually every fighting group in Syria. They are the best trained, most disciplined, and have attained the most battlefield success. Whether they can drive an entrenched ISIS out of a major urban area without even greater U.S. assistance remains to be seen. What is already known, however, is that this support is angering our only NATO ally in the region, Turkey.
Turkish President Tayyip Erdogan was livid about  the U.S. decision to increase support to the SDF. Erdogan said of the reports, “I hope very much that this mistake will be reversed immediately… We want to believe that our allies would prefer be side by side with ourselves rather than with the terror groups.” Turkey’s presidential advisor, Ilnur Cevik, was far less restrained in his response.
“If [the U.S. pushes] further, our troops may not care about Americans anymore,” he said  on May 4. “Suddenly, by accident, a few rockets may well hit them.” In other words, our NATO ally is threatening to bomb American soldiers. This implied threat must be taken seriously—U.S. soldiers in combat vehicles have been patrolling  between Turkish forces and SDF in the vicinity of Raqqa to prevent clashes.
A few important strategic questions need to be answered: Are American strategic interests served by supporting the SDF to drive ISIS out of Raqqa, if doing so ruptures our relations with Turkey? Another question is equally important: Can the United States afford to give into Turkish pressure and abandon the Kurds who are possibly the most effective militia in the region, and a group of people who have a long, positive history with America?
Already Kurdish leaders are nervous, wondering what will happen to them after ISIS is driven out of Raqqa. Will Turkey feel free to attack the YPG again as they did  earlier this year? Once the Kurds have accomplished America’s tactical objectives in Raqqa, will we continue to protect them from Turkey? And possibly more important, will the threat to U.S. security by ISIS be diminished by their downfall in Raqqa? The answer may surprise you: Senior American officials have warned that after the loss of its territorial holdings, ISIS might represent a greater threat to the country than is currently the case.
In March, then-FBI Director James Comey spoke  at a national security conference in Austin, Texas. In his remarks, he said that once ISIS has been “crushed” and their territories liberated, hundreds or thousands of former ISIS fighters would flee Iraq and Syria. “Where are they going?” he asked. “They’re going to Western Europe, they’re going to Southeast Asia, they’re going to North Africa. Then what are they going to do there? These are the most radical of the radical who are not just radical in orientation but have been equipped with military battlefield experience and tactics.”
No longer burdened with trying to hold territory, it is possible ISIS may exert more effort into planning attacks against the U.S. Many American leaders and pundits have claimed we used military force abroad so that we could fight terrorists “over there  so we don’t have to fight them here.” As we’ve learned over the last 16 years, that simply isn’t true.
In the Daily Beast earlier this month, former FBI officer Ali Soufan noted that on 9/11 there were likely no more than a few hundred al-Qaeda members. But after invading and beginning what turned out to be a 16-and-counting counterinsurgency fight, al-Qaeda membership has exploded worldwide. “Al Qaeda in the Arabian Peninsula is thought to have more than 4,000 fighters under its command,” Soufan wrote . In Somalia, al-Qaeda affiliate al Shabaab  “has more than 7,000. In Syria, al Nusra boasts more than 20,000.”
It could well be that Washington risks a rupture with Turkey and loses American blood, yet eventually drives ISIS out of Raqqa—only to see the global threat of ISIS expand in the process.
It’s equally possible that the U.S. suffers a rupture in our relations with a NATO ally, irrespective of whether ISIS is defeated or not. Before the president and his closest advisors increase American military engagement in Syria, they should step back and conduct a sober assessment of the strategic environment. Otherwise, we may see yet another terror group escape to rise in larger numbers another day.
Lt. Col. Daniel L. Davis (Ret.) is a senior fellow for Defense Priorities and a former officer in the U.S. Army who retired in 2015 after 21 years, including four combat deployments.