What enables the people to control the government, is that they have rights. Under democratic constitutions, citizens have rights: the right to life, the right to speak, the right of assembly, the right to discuss, the right to information, the right to criticise, the right to worship (or not to worship), the right to publish, the right to property, the right to fair trial, the right to vote.
Furthermore, democratic constitutions impose on governments a duty to respect the basic rights of citizens, to protect those rights, and to maintain institutions dedicated and empowered to upholding citizens’ rights, such as an independent judiciary.
If a constitution does not enshrine basic rights and ensure institutions for their maintenance, it is not democratic. If it is democratic, it enshrines the protection of rights. Democratic rule is premised on a system of rights and is impossible without that grounding.
In non-democratic systems, people do not have a similar array of rights. Here, governments rule without the consent of the people and therefore, necessarily, in fear of the people. Such governments rule not for the people but usually for themselves or for the benefit of a minority or an élite. Autocratic governments cannot allow the people basic rights because that would give them the tools to challenge the governments’ right to rule. Under autocracy, it is governments that have rights, not people. A non-democratic constitution that effectively awards citizens basic rights is an impossibility.
Nor does any such constitution or political system exist. Non-democratic systems can be more or less hard but they all, by definition and necessity, deny citizens basic rights.