Cairo Answers Riyadh

Egypt's pledge on 18 October means every capital Riyadh reportedly asked for air-defence help in September has now promised support or is reported to be giving it, and the UAE is again paying Yemeni fighters it cut off in January. Washington, the kingdom's main supplier, is giving intelligence and targeting. US interceptor stocks are heavily depleted and will take years to rebuild, but whether that shortage is what assembled this coalition, or treaty obligations and Gulf money did, the record so far cannot say.

On Sunday Egypt's National Defence Council, chaired by Abdel Fattah al-Sisi, promised Saudi Arabia "all necessary and possible forms of support" to defend its territory, resources and holy sites. Sisi has asked parliament for authority to send troops and equipment abroad. The vote slipped by a day and is expected on Monday or Tuesday. What Egypt will send has not been said.

The timing traces back to mid-September. Regional officials said then that the kingdom was running low on interceptors and had asked France, Britain, Pakistan and Egypt to deploy air defences, and one of them said the outreach began because American stocks had dwindled. Pakistan and Turkey said at the time that no request had reached them. Five weeks on, Pakistan has tens of thousands of troops in the kingdom helping with interceptions, France is sending systems to protect Yanbu, Turkey is supplying defensive and technical aid and Britain is counted among the backers. Cairo is the last name on the list.

Washington's place in this is narrower. Riyadh asked for American strikes on the Houthis and was reportedly refused. It received targeting help and intelligence sharing instead.

The second change is inside Yemen. The UAE has agreed to resume salaries for government-aligned forces, most likely the Southern Giants Brigades, which it stopped paying after January's Saudi-backed offensive reversed Emirati gains in the south. Saudi aircraft are to fly in their support. Saudi Arabia's defence minister was in Abu Dhabi on Sunday.

Those aircraft are now contested. A Houthi surface-to-air missile brought down a Saudi F-15 over Marib on 15 September. Another struck a Typhoon over Saada on 14 October. On 17 October a Saudi AH-6 light attack helicopter crashed over Najran with both pilots killed, which Riyadh blames on a technical fault and the Houthis show on video as a shoot-down.

The case for the shortage reading is real. During the 39 days of strikes on Iran before the April ceasefire, the United States fired an estimated 1,060 to 1,430 Patriot interceptors from a pre-war stock of about 2,330 and up to 290 of some 360 THAAD rounds. Restoring those inventories is expected to take three years or more, and Germany's new Patriot production is already promised to European users and Ukraine. Ukraine has reportedly run out.

Other explanations fit the same facts. The Mecca defence pact binds Pakistan and Turkey to Riyadh on paper. Egypt has lived on Gulf money since 2013. And a campaign that has killed at least 19 people in the kingdom and closed airports would draw allies with or without a stock problem.

Two markers will separate these readings. One is what Egypt actually deploys, and whether any partner brings interceptors of its own. The other is any on-record figure for Saudi Patriot and THAAD stocks, which no government has yet given.