Should researchers disclose their political interests in publications? Scenario: A researcher, who is also a member of the political party A, investigated the impact (e.g. on public health) of specific actions or policies (e.g. strikes or health expenditure cuts) belonging to the rival party B.

Assuming that the research motivation is scientifically justified, the methodology is sound, the results are "unbiased" and reproducible, and support was only received from an independent body (e.g. a research council), should the researcher disclose his/her political motivation in the publication?
The researcher should probably disclose any bias she knows she has, though outside of potential biases due to funding of the research (think drug companies funding studies for their products), I don't think this is done much. Prominent public intellectuals usually wear their biases on their sleeves, so reviewers are often pretty aware of them. I'm not sure matters as much for less well known academics unless there's a worry that they were cooking the data.