Either or parallelism confusion

A good approach is to try breaking the parallel structure into two pieces. Then, fit each piece back into the sentence, and make sure that it fits correctly. If each piece fits separately, and the two pieces have basically the same grammatical role (here, they're modifiers), the parallelism is good.

Here's what that would look like here:

1. If America allows China and Russia to establish regional hegemonies, consciously, it will have given them a green light to pursue their interests by brute force.
2. If America allows China and Russia to establish regional hegemonies, because its politics are too dysfunctional to muster a response, it will have given them a green light to pursue their interests by brute force.

Those are both good sentences, so you're almost certainly good with the parallelism.