Final answer:
The elderly population or seniors are primarily involved in the general enrollment of Medicare, as it is designed for those 65 and older. They are politically active, with a higher voter turnout influencing healthcare policy.
Step-by-step explanation:
The group particularly involved in the general enrollment of Medicare is the elderly population in the United States. Since Medicare is a health insurance program aimed at providing coverage for those 65 and older, this age group is not only the chief beneficiary of the program but also serves as a strong interest group influencing political decisions. As evidenced by their high voter turnout, the elderly population is politically active, underscoring their vested interest in policies about Medicare and other health insurance programs.
According to the U.S. Census, there's a notable difference in the participation in presidential elections between the elderly and the younger population, with a significantly higher percentage of older voters casting their ballots. This high engagement reflects the influence this demographic wields over policy decisions, especially concerning healthcare programs. Besides Medicare, other government-funded health-care programs like those for military veterans and for children with low-income families are also an important part of the health insurance landscape.
Medicaid is another significant healthcare program in the U.S., which, as of 2012, enrolled around 67 million people, with nearly half of them being children. Yet, in terms of healthcare expenditures, a large portion goes to the elderly and other groups like the blind and disabled, highlighting the distribution of healthcare resources.