In 1982, Mancur Olsen conducted a detailed evaluation of the factors that go into the decline or rise of nations, presenting some compelling arguments for the natural tendencies of groups and coalitions, whether small or massive, to fall apart after a while. His first argument is a paradox: that large groups, if composed of rational individuals, will not act in the group interest. The paradox is that the gains that come from membership in the large group are minute for each member, and that non members can also enjoy those gains without contributing!
In the case of a declining nation, the populace of citizens is challenged to reconcile the amount that they pay in taxes and volunteering with the monetary, social and intrinsic gains that they receive from the group effort. Two things happen with citizens who have an over dependence on services as opposed to contributions; and with immigration and migration, where the net costs of the non citizen migrant exceed their contribution to the whole as opposed to the profits of the corporations who hire them or the groups who favor free immigration. As a result, the funds that would be directed to maintaining infrastructure, services, and other goods are diverted to supporting those who do not contribute, polarizing them against those who do.
In a second paradox, governments must make sure that there is some reason for the populace to view the benefits that are provided in order to justify their existence. If the benefits are viewed a given, then no one would volunteer to pay taxes, go to work to leave the welfare system, or save for their retirements. As a result, taxes must be compelled and tax laws must be enforced.
Next, the increasing length of time that government officials and leadership stay in power works with the increasing length of time that a government structure exists to create opportunities for corrupting and manipulating the systems to serve the limited interests of a few.
Even though the populace may have the power to determine who is allowed to serve, the rise in voter apathy causes a relative few to hold the actual voting power. Corruption in voting systems can eliminate unwanted voters, and a corrupted court system can support election results that are suspect.
The increasing diversity of the population along with the increasing diversity of desire creates rifts that make it difficult to aggregate public desire to a national level and to introduce legislation and programs that satisfy even a majority of the population.
When the corporate and powerful interests have more input and success in influencing government decisions than the populace, the issue of voter and citizen disenfranchisement balloon into public outrage in a fractured environment of political, ethnic, economic, social, religious and extremist polarization among the populace. Increasing fears that organized and secretive groups actually hold the power lead to conspiracy theories and even more erosion of trust, respect and affection for the traditional government.
At some point, a declining nation is left with little respect among the other nations. There is a crumbling infrastructure, an inability to populate the military, a failed education system, a fragile economy, excessive taxation, perceived whole scale corruption, inability to provide a defense against foreign and domestic enemies, loss of essential services, loss of ability to make income to survive, and loss of affection for the existing government system.