Answer:
They are spending more than what they have in the Federal budget causing the national debt to increase.
Step-by-step explanation:
A government budget is considered to have a 'deficit' if the amount of money required to pay for all government programs is more than the amount of money that they have in their disposal.
When this situation happen, the government typically have two options. First is to increase the tax rate that the citizens have to pay in order to increase their budget. The second is they can borrow the required difference from another country. This what cause the increase in the national debt.