When others threaten your security or rights, certain measures may be necessary to protect you. But it doesn't follow that you may take those measures if another party has assumed responsibility for taking them on your behalf. As Thomas Hobbes argued centuries ago, when we leave a "state of nature" and enter civil society — which features the rule of law rather than anarchy and vigilantism — we transfer some rights to a government whose job description includes protecting us from various common threats. For example, the police, an arm of the government, are permitted to pursue criminals, forcibly apprehend them and bring them to justice. As private citizens, we generally lack the authority to perform these actions.