As a manager, do you think your responsibility is fully engaged in the event of failure following a decision taken under the inflence the company's owner?
The responsibility of the Manager is to Manage the Affairs of the Business in a Positive and Profitable manner.
Having said that if the manager Knew of a Negative decision That will be made, His responsibility would be to Document his views Via mail to The People or Directors in Charge.
Once the Mail is Sent You are Absolved of your Duty in that Regard, However should the situation be such that, A negative decision was made by the director, Your Responsibility would be to follow through his wishes based solely because he is your superior. At the same time, put in every effort to implement his plan as best possible. Should the Venture Fail then Best to Stop the Blame Game.. and start the process of identifying the problems then working on the solutions. Take what works .. discard whatever does not work. And Playing the Blame is the Biggest Downfall.