The best thing the government can do
... is leave people alone.
Sure, there's a role to play in moderating individuals' behaviour where it affects other people and you can argue a good point that it should provide some sort of safety net for people who fall out of society.
However for everyone else, who makes a conscious decision to do (or not to do) something that doesn't impact on the wellbeing of others, they should just be allowed to get on with it. By all means educate people into the consequences of their actions (whether those actions are drinking, smoking, voting or anything else) but if people are to be trusted with the power to elect governments, the same principle should be applied to how they conduct their personal lives.