In the end, the Somali defeat in this war is going to make the situation even worse in East Africa. Ethiopia might go for round two of the Ogaden War in the 80s or 90s (either under the Derg or post-Derg government) in light of the collapse of Somalia which will be akin to the one following the Ogaden War OTL. In Kenya, tensions in the Northern Frontier District will be far worse than OTL and take a lot more effort and bloodshed to put down.
Tanzania and Uganda are different than Kenya. Tanzania was not exactly a friend to the West (as they were non-aligned). Kenya was much more Western-aligned. And we're talking about a country which TTL already started and won a war against Ethiopia. The Kenyan leadership can easily present the conflict in the context of the Cold War, especially in light of the Soviet invasion of Afghanistan. Kenya can call on anti-communist forces in Britain and the US, which if Ronald Reagan is elected president, will be even more of a problem for the Somalis (not that the Carter administration would be much better for the Somalis). American and British advisors will be helping the Kenyans every step of the way.
True, but the main cause of the war was Tanzania being a base for exiles from Idi Amin's rule who were involved in numerous actions to overthrow him. Kagera was secondary. Compare that to Somalia, where Siad Barre appears to have imagined a campaign of Somali national unification where step one was Ogaden, which if successful, step two was the Northern Frontier District of Kenya. It's hard to present the war as anything but yet more blatant aggression for the sake of nationalism. Yes, the Somali minority in Kenya was treated horribly at the time, but it looks bad to start an international war over that.
Commonwealth members have no legal obligations to each other. Idi amin was Soviet backed and expelled a large number of British citizens and nationalized a lot of British assets in Uganda.
Tanzania and Uganda are different than Kenya. Tanzania was not exactly a friend to the West (as they were non-aligned). Kenya was much more Western-aligned. And we're talking about a country which TTL already started and won a war against Ethiopia. The Kenyan leadership can easily present the conflict in the context of the Cold War, especially in light of the Soviet invasion of Afghanistan. Kenya can call on anti-communist forces in Britain and the US, which if Ronald Reagan is elected president, will be even more of a problem for the Somalis (not that the Carter administration would be much better for the Somalis). American and British advisors will be helping the Kenyans every step of the way.
They did claim and tried to annex Kagera Region
True, but the main cause of the war was Tanzania being a base for exiles from Idi Amin's rule who were involved in numerous actions to overthrow him. Kagera was secondary. Compare that to Somalia, where Siad Barre appears to have imagined a campaign of Somali national unification where step one was Ogaden, which if successful, step two was the Northern Frontier District of Kenya. It's hard to present the war as anything but yet more blatant aggression for the sake of nationalism. Yes, the Somali minority in Kenya was treated horribly at the time, but it looks bad to start an international war over that.