The authors of the Constitution also created a federalist system. Federalism is a system of government in which power is divided and shared between two entities—in this case, the national government and state governments. This structure reflected the delegates' experiences with both the weakness of the central government under the Articles of Confederation and what they perceived as too much central control under Britain's unitary system of government. In a unitary system, the central government holds most or all of the governing power. The Constitution's federalism established a strong central government, attempting to improve on the articles government, but still gave many powers to the states, to prevent the potential abuses of an unchecked national power.To prevent any branch of the national government from becoming too powerful, the Constitution includes the separation of powers. This principle establishes the division of the legislative, executive, and judicial functions into distinct, independent bodies. Buttressing the separation of powers by preventing the abuse of power by any one branch, the Constitution institutes a system of checks and balances. This principle ensures that the different branches of government have the ability to stop actions of the other branches under defined conditions. Checks and balances also dictate how the branches work together. For example, the legislative branch makes laws, but the president can veto a law. The judicial branch can check the legislative branch by ruling a law unconstitutional. In turn, the president appoints judges, keeping a check on the judicial branch, and the Senate must approve those appointments, providing a check to executive power.