The answer is Yes. Due to some recent advancement in the field of life, a government can be ousted through various methods, such as abusing the power or vote of no confidence in a parliamentary system, and in some aspect or cases through impeachment or dissolving parliament to trigger new elections, this very process depends on the system of the country government and their constitution.
It's play a vertal role on the system of the country policy.
What is even the point of this?
Any government can be ousted from it's position of power, there have been governments which were considered to be eternal in human history, like the government of the Soviet Union or the government of the Roman Empire, it was just matter of time before all of them fell by their own weight and got replaced by a new administration.
If you want to actually discuss about an specific government, period of history or geographical location, then you should specify it in this thread, instead of talking in such a wide terms, it just confused people who may be interested in engaging in this conversation with you and with others here.