The major opposition in Russia is not Navalny who is an irrelevance. The best thing that can happen is that he should be allowed to stand and show the low support that he will get. But he deliberately breaks the law in order to appear to be a dissident. That is his value to the West, not his popularity.
The West has a huge responsibility of not interfering with nascent democracies. Democracy can never be forced as it needs painstakingly slow background civic structures. The colour revolutions that the west foisted on many countries have not resulted in real democracy or stability. The west can in many way be accused of stunting democracy in these parts of the world because any democracy in the world has to have the stamp of approval of western hegemony.