"The only reason US hasn't ended this earlier is because it's in their interest to drag this out and cause not only a military default for Russia but also end P

"The only reason US hasn't ended this earlier is because it's in their interest to drag this out and cause not only a military default for Russia but also end Putins' reign. " I don;'t think this is a at all the 'only' reason, but it certainly stands to reason, and it is exactly what they should continue to do. pushing for a ukraine victory while putin is still in place might well trigger a 'cornered rat' response. Exhaust them, to the point that they are unable to fight on, and the regime will perhaps collapse on it's own.