 Political theorists propose standards that identify legitimate uses of political power. Some adopt a principle of public justification. A public justification is a kind of rationale for exercising power and control. It is public because the rationale, or group of rationales, is one that members of the public can accept. Put another way, to treat people as equals, we must ensure that political power is justified for or to them by their own lights, so a public justification thus consists of reasons the public can recognize as valid. Those who adopt a public justification standard are often called public reason liberals. Liberal institutions (freedom of speech, the rule of law, democracy) are publicly justified, but illiberal institutions are not. Diverse perspectives within the public will reject non-liberal institutions.