Locke defines tyranny as "the exercise of power beyond right." A just leader is bound by the laws of the legislative and works for the people, whereas a tyrant breaks the laws and acts on his own behalf. Locke notes that any executive body--not just a m onarchy--that ceases to function for the benefit of the people is a tyranny. He then points out factors that limit the people from hastily opposing the government. These include: sanctity of the executive; faith that laws will prevent necessity of for ce; and the fear that a small group of individuals will never overthrow powerful leaders with success.
In Chapter 19, Locke finally arrives at the question of forming a new government. When the state ceases to function for the people, it is dissolved, and may be replaced. This occurs when the legislative is changed or usurped by a tyrannical executive po wer, when the legislative or executive breaches its trust, or when the executive ignores its own duties and renders the law meaningless, reducing society to chaos.
When the government is dissolved, the people are free to reform the legislative in order to re-create a civil state that works in their best interest before they fall under tyrannical rule. Why does this doctrine not lead to excessive unrest and f requent rebellion? For several reasons: people are slow to change their old habits and customs; if the people are miserable, they will rebel under any system; and finally, revolutions occur only in the event of the leadership's flagrant abuse of p ower or breach of trust. This system, Locke argues, protects against rebellion because it allows the people to change their legislative and laws, rather than resorting to force to overthrow them. Locke also notes that all concerns about revolution are f oolish, because they represent a fear of a righteous process: it is rightful and dignified for people to rebel against unjust oppression.
Locke then calls upon William Barclay, a protector of the rights of kings, to describe situations in which people may overthrow the kings. Locke uses Barclay to prove that even a great defender of royal privilege concedes that a king may abdicate himself by abusing the power of his position, and at that point the people have the right to overthrow him.
Who judges when the leader has abused his power to such an extent that he may be overthrown? The people, Locke says. The people are the best judge of whether their protector is protecting them. Locke ends by noting that, as long as society lasts, the p ower that each individual gives it cannot revert back to the individual, and, so long as any government lasts, the power that the society gives the legislative cannot revert back to the society. Either of these institutions may be destroyed by the revers ion of the powers vested in them, people always being free to "erect a new form, or under the old form place it in new hands, as they think good."
Locke completes his picture of a just civil society by returning to his original impetus for writing the Second Treatise--the dissolution of government in the face of tyranny. Locke has lain his groundwork so soundly that his argument for the dissolution of government requires no new ideas, only a synthesis of everything covered so far. Civil society exists to protect the property and liberty of its members--if something break s down anywhere in its government and it no longer fulfills this function, something has gone awry and the people have a right to rid themselves of that government. Where does this right come from? From the natural rights described by Locke starting as far back as Chapter2. If the government in power is not working for them, it is not a just government, and people would be better off in a state of nature.