The success of contemporary democracies is indeed fundamentally predicated on the state's ability and willingness to limit its own power. This principle, often termed 'limited government,' is a cornerstone of liberal democracy and serves multiple crucial functions.

Firstly, protection of individual liberties and rights: By establishing constitutional limits, such as bills of rights and judicial review, the state is prevented from infringing upon the fundamental freedoms of its citizens. This ensures that individuals can express themselves, associate freely, and participate in political life without fear of arbitrary state action, which is essential for a vibrant democracy.

Secondly, prevention of tyranny and authoritarianism: Unchecked state power can easily devolve into authoritarianism, where the government acts without accountability. Mechanisms like separation of powers (legislative, executive, judiciary), checks and balances, and federalism distribute power, making it difficult for any single branch or level of government to become too dominant. This institutional design safeguards against the concentration of power that could undermine democratic principles.

Thirdly, accountability and responsiveness: When state power is limited, government officials are more accountable to the people and the law. Regular elections, transparency in governance, and an independent judiciary ensure that those in power can be held responsible for their actions and that the state remains responsive to the needs and preferences of its citizens. This fosters trust and legitimacy in democratic institutions.

Fourthly, rule of law: A limited state operates under the rule of law, meaning that all, including those in power, are subject to the same laws. This provides predictability, fairness, and stability, creating an environment where citizens can plan their lives and engage in economic and social activities with confidence. It prevents arbitrary decision-making and ensures equal treatment before the law.

In essence, a state that limits its own power creates the necessary conditions for a free, just, and stable society where democratic values can flourish. Without these limitations, the very foundations of democracy – individual freedom, political participation, and accountability – would be severely eroded, leading to a less successful and potentially oppressive political system.