According to Polybius, a mixed constitution is considered to be the best state. He considers three kinds of constitution; kingship, aristocracy and democracy. A mixture of this constitution will give rise to a best state. Very contrasting to what Aristotle had stated in his book, Politics, that he did not identify what considers to be a best state but instead he identify only the forms of government that will constitute to be the best state. Though, Aristotle did not suggest any to have the best state, but the principle behind what Polybius had stated to what to be a best state is in reference to what Aristotle had suggested to the kinds of government that he identify.
As to what Polybius stated that the three kinds of constitution if taken separately will not constitute the best state. If a constitution is formed in one principle is dangerous. To prove his statement, that the combination of constitution will give rise to the (considered) best state. He cited an example to what Lycurgus of Sparta did.
Lycurgus study different kinds of constitution and draw up a constitution in reference to the constitution that he studied. He did not make his constitution simple and uniform, but united in it all the good and distinctive feature of the best governments of the constitution that he considered. Polybius considered that work of Lycurgus, of combing the different features of the constitution of the best governments, to prove that the best state will not only constitute from a single kind of government.
Polybius identifies the three different parts of the state: the consuls, the senate, and the people. Though, the combination of the three varieties of government is difficult to speak whether the whole system is aristocratic, democratic and monarchial. But according to him, it is natural. If one fixed his one’s eye on the power of the consul, represented monarchial principle of the constitution; senate, the constitution seemed to be aristocratic; democratic, the power of the masses – the popular assemblies. Then the basic power of the government is to check and balance the other two in order that there will be no other will be over-powering the power of the other. The role of the consuls is to represent embassies to the senate. The senate has the control of the treasury, all revenue and expending regulated by it. Without the consuls, the entire system will be entirely aristocratic – the senate will manage all the business connected with them. After the consuls and the senate, the only left is the question, what part in the constitution is left for the people? Now, this is the important part that is left for the people – democracy, for it is the people who can grant office to the deserving.
What comes after is that the explanation of Polybius of the different parts of the state: the consuls, the senate, and the people or the popular assemblies. These three parts of the state must compliment each other because they need the support of each other in order to have a best state that has its own functions and specializations. The consuls appears to have absolute authority in all matters necessary for carrying out his purpose, but all this absolute power requires the support of the senate and the people. And if he leaves with his legions, they also require constant supplies. The senate obliged to pay attention to the commons in the public affairs, and respect the wishes of the people because it is the people have the power of passing of rejecting any such measure. Why will the senate do this, that they always take account of the masses. Because the senate must pay attention to the masses and must pay attention to the popular will.
Polybius had come into this, the mixed constitution, to come up a best state. The main point is to identify what would be the kind of government will be the best to constitute the best state, which for him would be the combination of the three. Why, because Polybius saw in monarchy, aristocracy, and democracy the three chief forms of government. He consider that these three chief forms of government could be easily become what would be their perverted form, monarchy could be easily become tyranny, aristocracy sink into oligarchy, and democracy into mob-rule, as what Aristotle stated in his book, Politics. Polybius considers the Roman constitution to be the best. He believes that he found near-perfect balance among these three principles: the consuls, the senate, and the popular assemblies.
No matter what would be the form of government will be use, it is still a big factor of what will be the response of the people and their orientation on political matters. Polybius is right in mixing the constitution because there is no exact form to suit in every portion of the earth because of the diverse individuals that is present.