
Provide an environment where speaking up isn't likely to result in termination or a poor performance review.
Leadership needs to develop a politically-neutral environment. Anybody who doesn't tow the party line is afraid of losing their job or of poor performance reviews for not being "Googly".
Remove the political elements associated with being at the company. Only approved political opinions are allowed to be expressed at work, and loudly at that. Anything else may result in down-rating or termination.