Answer:
A way in which the government might respond to rising threats to national security through fiscal policy would be by increasing military spending.
Step-by-step explanation:
External threats to national security are those situations, caused by policies or events generated by other countries or foreign organizations, which constitute a risk to the internal well-being of the United States.
To counter these threats, deterrence and immediate response power is needed, which is only provided by the armed forces (which intimidate and in turn respond to aggressions). Therefore, increasing public spending and allocating it to military expenses is a way of responding to threats to national security, since a greater military presence implies a greater capacity to respond and prevent these threats.