Let’s start by explaining what this fight is not. It is not a clash of civilizations. Muslim scholars are outraged about the Islamic State’s brutality and perversion of Islam, calling its savagery deviant and heretical. Sunni and Shiite alike have joined forces against this outrage. The coalition represents a unified response, as evidenced by the remarkable and unprecedented participation of five Arab countries in the air strikes in Syria. And that’s just the beginning. There is a role for every nation, from helping to dry up outside funding and stopping the flow of foreign fighters to taking direct military action and providing humanitarian assistance.

This is not the prelude to another US ground war in the Middle East. President Obama has said repeatedly that US ground troops will not engage in combat roles. He means it. I volunteered to serve and fought in a war I came to believe was a mistake. I take that lesson seriously. This will not be another one of those interventions.

Finally, this campaign is not about helping President Bashar Assad of Syria. We are not on the same side as Assad — in fact, he is a magnet that has drawn foreign fighters from dozens of countries to Syria. As the president has said, Assad lost legitimacy a long time ago. We are embarking on an important effort to train and equip vetted members of Syria’s opposition who are fighting the Islamic State and the regime at the same time. By degrading the Islamic State and providing training and arms to the moderates, we will promote conditions that can lead to a negotiated settlement that ends this conflict.