If your answer is yes, then you are supporting an idea that is the mother of all dictators. Prevention is the act of the government forcibly stopping an individual from making his own choices about his life's activities. Prevention is implemented through regulations. The distinction between the two is profound and the answer to this question leads a nation either in the direction of totalitarianism or freedom.
Prevention leads to totalitarianism.
Protection leads to freedom. There is nothing in between, except in a society, such as we have today, which is in transition to one or the other of these conclusions. For statists, to ask a question is to find an immediate answer. Enact legislation which will wipe out your freedom to make the choice to smoke. Create laws which eliminate your freedom to choose to do something risky.