The mounting security concerns that have Egypt poised to send ground troops into Yemen also seem to have pushed Cairo into making nice with Ethiopia after years of tensions over the construction of a massive dam on the Nile River.

Egypt, Ethiopia, and Sudan reached a preliminary deal this week that could help whisk away the bad blood over Ethiopia’s plans to build the $5 billion Grand Renaissance Dam project. On Wednesday, Egyptian President Abdel Fattah al-Sisi — who as defense chief in 2013 appeared to threaten to use Egyptian troops to stop the dam’s construction — had a kumbaya moment in his address to the Ethiopian parliament, promising a new era of trust and friendship between the two nations.

Egypt and Ethiopia have been at loggerheads for years over the project. Cairo worries that an upstream dam will choke the Nile River water flows that are literally the country’s lifeblood. Power-starved Ethiopia counters that the 6,000-megawatt hydroelectric facility is needed to bring more power generation to the region, and will also help to better manage water use along the river. Ethiopia ignored repeated Egyptian entreaties to halt construction of the dam, which is now almost half-complete.

This week, though, much of that bickering appeared to evaporate with the signing of a 10-point “Declaration of Principles” that accept the dam’s inevitability and seek to manage its impact on neighboring countries. The three-way accord between Egypt, Ethiopia, and Sudan will hardly end contentious fights over regional water management; there are decades-olddisputes over which countries have the right to Nile River waters, and this week’s deal doesn’t address the trickiest outstanding issues regarding the dam’s operations. That includes determining exactly when and how fast Ethiopia will fill the reservoir behind the dam. Since the reservoir can hold about one year’s worth of Nile river flow downstream, figuring out just how and how fast to ease the dam into operation is an existential concern for Cairo.

But the accord does pluck one painful thorn out of Egypt-Ethiopian relations at a particularly unsettled time in the region.

But the accord does pluck one painful thorn out of Egypt-Ethiopian relations at a particularly unsettled time in the region. On Thursday, Saudi Arabia and other Arab states launched military strikes against Iranian-backed Houthi rebels in Yemen who have upended the regime of current President Abed Rabbo Mansour Hadi.Indeed, that instability may have been one of the reasons that Sisi has sought to defuse tensions with Addis Ababa. Ethiopia is helping fight al-Shabab in Somalia, and Sisi cited mutual counterterrorism goals in his address to Parliament. At the same time, the Houthi offensive in Yemen has sparked concerns about security off the coast of Yemen, including the key chokepoint at Bab el-Mandeb. That is particularly worrying for Cairo, which has ambitious and costly plans to expand the Suez Canal and turn it into the linchpin of future economic development. On Thursday, Sisi said in a statement that his air force and navy had already joined the fighting, and that he was ready to deploy ground troops “if necessary.”

Analysts at the German Institute for International and Security Affairs, or SWP,  suggested that the diplomatic breakthrough over the dam could be due in large part to Egypt’s growing security headaches, especially around the future safety of the Suez Canal and its seaborne approaches.

“[A]bove all Egypt possesses a strong strategic interest in the security situation in the southern Red Sea,” wrote SWP analysts Tobias von Lossow and Stephan Roll in February. “Especially in light of the latest developments in Yemen, Egypt appears to possess almost no alternative to closing ranks with Ethiopia, as the only regional power in East Africa with an effective army,” they wrote, concluding that security played a “decisive role” in Sisi’s change of tack on the dam negotiations.

Granted, there is still plenty of scope for future problems. The accord only addresses the Grand Renaissance Dam, not water-sharing along the Nile basin. And even the declaration of principles has been met with skepticism in Cairo; a former water minister railed against what he saw as a sellout of Egypt’s historic water rights. At the same time, there is still a surfeit of angst over the dam’s construction and safety, as well as its ecological impact, such as on the Sudd marshlands in South Sudan.

But after years of poisoning the atmosphere between Cairo and Addis Ababa, the controversial dam might yet be able to channel the two countries into a closer and more productive relationship, at least as far as security is concerned.

Photo credit: ZACHARIAS ABUBEKER/AFP/Getty