[leto_ii]

This is not a matter of class balance that much. If you want to predict which of two parties somebody will vote with, the most natural framing is that of binary classification.

For that you need to threshold your predictions. Ideally you'd like your model to generate a bimodal distribution so that you can threshold without many false positives etc.

[jncfhnb]

Yes but the prompt here states that all we know is the probability is either 0.55 or 0.45. By definition this is the best model you can produce.