Rather than ever more oppressive laws that strip the people of power, it would be more effective to consider the motivations of those who would commit violent crimes. It is the pervasive poverty and egregious wealth inequality that drives most crime, along with our worsening system of injustice. Similarly, we should be considering the causes of terrorism, rather than allowing our leaders to exploit it to cow us with fear.
When the minimum standard of living becomes sufficient to afford everyone a decent existence, such problems will naturally disappear. Desperate and hopeless people will do terrible things, and no amount of force is going to prevent that. Fortunately, outside of the mentally ill, few would risk a comfortable life to engage in serious criminal activities. (Assuming a reasonable set of laws and fair enforcement.) Even the religious fanatics would see their numbers dwindle, with no oppression needed.
With abundant and cheap energy, eliminating poverty is entirely possible. That result will not come from energy conservation and renewables alone though; it will require nuclear power. Objectively speaking, nuclear energy has the lowest cost and least environmental and health impact of any energy source, and advanced reactors can do better yet. The Star Trek economy is within reach, if only people had the courage to embrace a change for the better, and to rein in the special interests.