What happened in WW 1 and WW 2 ? Russia which didn ' t even exist at the time but let ' s assume USSR for convenience was an ally in both scenarios where does that even come in this context . In fact , Russia was the major factor in pooping all over Nazi Germany . If you are talking about the cold war than yeah , Western Europe depended a lot on the US army for a sense of safety . Which is what happens when you have 2 superpowers wrestling for influence over the world . But the USSR is no more , and we ' re not in the Cold War anymore . Russia is a mere shadow of what the USSR used to be and Europe has had time to recover from being torn to shreds in two back to back world wars . As to what is the point ? I could ask you what the point of an US army is . Do you think Mexico or Canada is going to invade ? The point is the same as every other army in the world . And they sometimes do similar operations as the US does now , look at Operation Serval in Mali for a recent example .