Final answer:
Policy-makers face challenges in contemplating large changes in spending levels for the federal budget, including difficulty cutting spending on popular programs, potential negative impacts on the economy and public services, and political resistance.
Step-by-step explanation:
When contemplating large changes in spending levels for the federal budget, policy-makers face several challenges. One challenge is the difficulty of cutting spending on popular programs, such as defense, education, agriculture, and transportation, which may be necessary to balance the budget.
Another challenge is the potential negative impacts on the economy and public services that could result from spending cuts. Additionally, policy-makers may face opposition and political resistance to any changes in spending levels. These challenges make it complex for policy-makers to make significant changes to the federal budget.