On March 26, Egypt announced that it would join the Saudi-led military campaign against the Iranian-backed Houthi takeover of Yemen.

While the extent of Egypt's involvement is still to be determined, Cairo's decision reflects two considerations: addressing the theoretical threat that the Houthis pose to maritime security in the Red Sea, and helping its Persian Gulf allies resist Iran's hegemonic ambitions.

Egypt was not eager to enter the conflict because its prior military intervention in Yemen was extremely costly. Approximately 26,000 Egyptian soldiers died fighting Saudi-backed royalists during the 1962-1970 Yemeni civil war. Moreover, by entering the current conflict, Egypt risks stretching its military thin, since it is already fighting ISIS-affiliated jihadists in Libya and the Sinai — without much success on either front.

The Houthi seizure of Aden on March 25, however, seemingly forced Cairo's hand. From Egypt's perspective, Houthi control of the southwestern coastal city threatens maritime traffic in Bab al-Mandab, the strait that connects the Red Sea to the Gulf of Aden. Cairo worries that the Houthis might threaten Suez Canal traffic, which has been one of the Egyptian government's most reliable revenue streams. Over $5.4 billion in canal tolls were collected in 2014 alone, and Egypt is currently digging a second canal that it anticipates will increase revenues to $13.5 billion in 2023.