From the perspective of historical philosophy, the constitutional system is an important part of the modernization of the rule of law. Analyzing the concept and connotation of the modern constitutional government system, it can be seen that the constitutional government system is a modern state system of the modern constitutional system of the rule of law and democracy. The basic principles of constitutional government are summarized into four points: people's sovereignty, basic human rights, decentralization and checks and balances, and the rule of law. Among them, "is the government committed to realizing constitutional government?" Is an important goal state and verification standard for implementing the rule of law and building a country ruled by law, which determines the value orientation of constitutional government.
In the historical period when the constitutional system was formed, the natural law school always played an important role, especially the classic naturalist law. It claims that there is a natural law higher than the real law, which is a universal and eternal natural law, and therefore a natural right derived from "nature and nature" is born, supported by the transcendental authority of natural law. Legal thinking. It not only constructs the ideological platform of the modern Western constitutional country, but also provides the value norms of the modern Western constitutional system, and presupposes the legal foundation of the modern constitutional country. The text will start with the main ideas in classical natural law to prove that the natural law school represented by classical natural law is the theoretical foundation of modern constitutionalism under constructivism.

Hanchao Liu. Natural Law as the Foundation of Constitutionalism. Academic Journal of Humanities & Social Sciences (2020) Vol. 3, Issue 4: 1-12. https://doi.org/10.25236/AJHSS.2020.030401.

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