Introduction
Aging is defined as a gradual and latent biological process that, with increasing age, leads to destructive changes in the physiological structures of the body and ultimately causes a decline in their function. Determining the age of onset of old age has always been a matter of disagreement among experts and researchers in this field. However, since 1999, the United Nations Commission on Population and Development has introduced the age of sixty as the starting point of old age. According to the "World Population Ageing" report presented by the United Nations, the world's elderly population in 2015 was more than 901 million, which was about 4.5 times the 202 million elderly population in 1950. In the same year, one in every 8 people was 60 years old or older.  With this trend, it is predicted that by 2030, one in every six people in the world will be elderly, and by this year, the elderly population in Europe and North America will increase by 25%, Oceania by 20%, Asia and Latin America by 17%, and Africa by 6%. Iran is no exception to this rule, and according to UN forecasts, Iran will have the largest increase in its elderly population in the near future. Currently, about 9.05% of the population over 60 years of age and 6.01% over 65 years of age and over live in Iran. If this trend continues, by the end of 2025, the population over 60 years of age and over will reach 11% and in 2050, it will reach 28%. Based on a comparison of the country's population age pyramid from 1976 to 1986, the country's population grew steadily (46.7%) (the period of hyper-fertility in the 60s); but since then, following the implementation of generation-limiting policies in 1991, population growth has been on a downward trend; to the extent that from 2001 onwards, instead of population growth, the number of elderly people has increased.
The statistics presented clearly show that Iran is facing an increase in the number of elderly people and that in the near future, Iran's population structure will be significantly older than in the past. Population aging changes not only affect Iran's age and gender structures, but also have broad consequences in economic, social, health, psychological, and political dimensions. However, in a significant part of previous studies and reviews, the political consequences of changes in the population age pyramid have received less attention. Population aging has broad and multifaceted implications that also affect the realm of politics and government functions. Since every social phenomenon has the potential to influence politics, the increase in the elderly population causes changes in the age pyramid and government orientations. The elderly is linking their demands to the government, and the government is forced to design and implement appropriate policies and measures based on the new conditions.
Materials and Methods
This research seeks to answer the question of what impact has population aging had on government functioning in Iran since the 80s? To answer this question, the Delphi method was used, and The researcher collected the views of 25 political and social science experts in the first stage through interviews, and then, from the data obtained, a closed questionnaire was prepared, which the experts responded to in three stages, and finally, a consensus was reached in the third stage.
Result and discussion
 In the preliminary stage of implementing the Delphi method, the researcher first collected data from a systematic review of previous scientific sources related to the topic of "The impact of population aging on government functioning in Iran since the 80s" and provided it to the members of the expert panel. In order to supplement this data, interviews were conducted with selected experts to elicit their views on the subject. After collecting the data from the interviews, a systematic content analysis was conducted on the responses. As a result of this analysis, 12 effects of population aging on government performance were identified from the experts' perspective, of which one effect, "decreased criticality," was eliminated due to lack of consensus among experts, and 11 effects of population aging on government performance,  such as intensifying the welfare nature of the government, the spread of populist tendencies, weakening authoritarianism, reducing responsibility for advancing development, reducing political mobility and vitality (such as reducing vitality, enthusiasm and excitement in holding elections, etc.), reducing transparency and accountability for advancing development, reducing oversight of relevant executive bodies for advancing development, the dependence of government legitimacy on the realization of costs and needs, the dependence of government acceptability on the realization of costs and needs, the dependence of loyalty and political support on the realization of costs and needs, and the dependence of political trust on the realization of needs, were confirmed by experts
Also, from the perspective of the panel members, "the dependence of political support on the fulfillment of needs" and "the dependence of government legitimacy on the fulfillment of needs" with 4.96percent; "the intensification of the welfare nature of the government" with 4.92 percent; and "the prevalence of populist tendencies in the government" with 4.88 percent have been among the most important effects of population aging on government functioning in Iran since the 80s.
Conclusion
Population aging, like variables such as age, gender, family structure, etc., is considered one of the fundamental topics in qualitative demographic studies. Although this trend reflects important achievements in the fields of public health, nutrition, and social welfare and indicates an improvement in the standard of living in human societies, in the absence of efficient management and a lack of scientific understanding of its path and consequences, it can create serious challenges for the economy, the health and treatment system, and sustainable development. The spread of the phenomenon of population aging in Iran not only affects the biological and social dimensions of human life, but its consequences also directly and indirectly cast a shadow on the political structure and performance of government institutions. Especially in a situation where the proportion of elderly people in society is increasing, it is not possible to analyze the functions of the government independently of the effects of this demographic change, because ignoring the political dimensions of this phenomenon can weaken the government's capacities in facing emerging challenges. Accordingly, the present study seeks to answer the question of what impact has population aging has had on government functioning in Iran since the 80s? To answer this question, the theory of non-commitment and feeling of relative deprivation and the Delphi method were used. The findings showed that, from the perspective of experts, the most important consequence of population aging on the functioning of the government in Iran since the 80s has been “the increased dependence of the government’s legitimacy and political support on meeting the costs and needs of the elderly” (average score 4.96%). Also, the intensification of the welfare nature of the government (4.92) and the spread of populist tendencies (4.88) were other prominent results. These findings reveal that the government, faced with the pressures of an aging population, increasingly sees its political legitimacy as dependent on its ability to provide financial resources and welfare and social services. Therefore, population aging has not only caused changes in the government's resource allocation system, but has also pushed its political orientations towards models based on welfare policies and populist tendencies.