On May 31, US Secretary of State John Kerry offered his most potent rebuke yet of Russia’s support for the Assad government — but not because of the inherent risk the sale of missiles poses to the people of Syria. 

The New York Times reported Kerry as saying, “[The sale of S-300 missiles to the Assad regime] is not, in our judgment, responsible because of the size of the weapon, the nature of the weapon and what it does to the region in terms of Israel’s security.” His statement is a clear example of what the world already knows — for the United States, its strategic red line doesn’t appear to be primarily the loss of human lives in Syria, but Israel’s security the way Israel defines it.

The United States had justification to act in Syria under the principle of the responsibility to protect civilians, but it has been reluctant for the past two years. While efforts have been appreciated to bring some kind of diplomatic settlement, Kerry’s recent statement aligning rebel interests with Israel’s strategic concerns — intentional or not — is a serious flaw. If the United States is to play a constructive role in resolving the conflict in Syria, then its offer of support should be exclusively on the merits of the humanitarian crisis and the legitimacy of the opposition’s role.

Clovis Maksoud is a former ambassador and permanent observer of the League of Arab States at the United Nations and its chief representative in the United States for more than 10 years.