There was no fighting by anyone, except for Yanukovych attacking Maidan protestors, until Putin sent arms and forces into the east. The US supported Yanukovych’s removal, but there is no way the US could have gotten tens of thousands of protestors to risk their lives at Maidan. The push to get rid of Yanukovych came from the Ukrainians themselves. Russia sent arms and troops into Ukraine in 2014, there was no “civil war.”
Then you had people like John McCain, Chris Murphy, and Asst Sec State Victoria Nuland working with and supporting the Neo-Nazi Svoboda and other protest groups. The US even hand-picked the new Prime Minister after the Maidan revolution.
The fighting in Donbas started soon afterward.