The US has nothing to do there.
Its a conflict within Ukraine.
Russia has nothing to do there either.
Its Ukrainian soil.
Ukraine, as an artificial state was de juro created by Lenin after a coup d'etet in Russia in 1917, consisting of Russian county of Novorossia. After the War, Stalin annexed Galicia to Ukraine, and a couple of decades later Khrushov robbed Russia of Crimea and anenxed it to Ukraine. Thus Ukraine was born. Now the Galicians have taken to arms and say that Ukraine is for Galicians, and that Russians must be killed. It does not change the fact that people living in Ukraine, in its Eastern part are Russian.
Russia has quite a lot to do there, in fact. It's a pity that Russia does so little to defend the Russians that are under siege there by the Galicians.
As for US - it has a strong lobby consisting of Ukrainia emigree, which basically bought up the American political top.
Let's take a hypothetical scenario. The Dutch-speaking citizens of Belgium start killing the French speaking ones, calling for full extermination of the French there, saying that Belgium is only for the Dutch. US sends lethal weapons to the Dutch-speaking residents and endorses the genocide. Should France just sit idly and see the French-speaking population of Belgium be exterminated?