Final answer:
The crowding-out effect decreases the effectiveness of expansionary fiscal policy by causing higher interest rates, which leads to reduced business investment and household spending.
Step-by-step explanation:
The crowding-out effect is a phenomenon where government borrowing leads to higher interest rates, which in turn discourages businesses and households from borrowing and spending. This can decrease the effectiveness of expansionary fiscal policy, which relies on tax cuts or spending increases to boost aggregate demand. Instead of stimulating the economy, the fiscal policy's impact may be weakened due to these higher interest rates reducing business investment and household consumption.
When the economy is near its potential GDP and the government runs large budget deficits, this increased demand can lead to inflationary pressures. In response, the central bank might implement a contractionary monetary policy to combat inflation, further increasing interest rates. The synergistic effect of government borrowing and central bank policy can then significantly crowd out private investment.