第30章政府予算と財政政策

Expansionary fiscal policy increases the level of aggregate demand, through either increases in government spending or reductions in tax rates. Expansionary policy can do this by (1) increasing consumption by raising disposable income through cuts in personal income taxes or payroll taxes; (2) increasing investment spending by raising after-tax profits through cuts in business taxes; and (3) increasing government purchases through increased federal government spending on final goods and services and raising federal grants to state and local governments to increase their expenditures on final goods and services. Contractionary fiscal policy does the reverse: it decreases the level of aggregate demand by decreasing consumption, decreasing investment, and decreasing government spending, either through cuts in government spending or increases in taxes. The aggregate demand/aggregate supply model is useful in judging whether expansionary or contractionary fiscal policy is appropriate.

Consider first the situation in Figure 30.11, which is similar to the U.S. economy during the 2007-2009 recession. The intersection of aggregate demand (AD₀) and aggregate supply (SRAS₀) is occurring below the level of potential GDP as the LRAS curve indicates. At the equilibrium (E₀), a recession occurs and unemployment rises. In this case, expansionary fiscal policy using tax cuts or increases in government spending can shift aggregate demand to AD₁, closer to the full-employment level of output. In addition, the price level would rise back to the level P₁ associated with potential GDP.

Should the government use tax cuts or spending increases, or a mix of the two, to carry out expansionary fiscal policy? During the 2007-2009 Great Recession, the U.S. economy suffered a 3.1% cumulative loss of GDP. That may not sound like much, but it’s more than one year’s average growth rate of GDP. Over that time frame, the unemployment rate doubled from 5% to 10%. The choice between whether to use tax or spending tools often has a political tinge. As a general statement, conservatives and Republicans prefer to see expansionary fiscal policy carried out by tax cuts, while liberals and Democrats prefer that the government implement expansionary fiscal policy through spending increases. In a bipartisan effort to address the extreme situation, the Obama administration and Congress passed an $830 billion expansionary policy in early 2009 involving both tax cuts and increases in government spending. At the same time, however, the federal stimulus was partially offset when state and local governments, whose budgets were hard hit by the recession, began cutting their spending.

Events were even more severe during the more recent pandemic-induced recession. In a single quarter (Quarter 2 of 2020), GDP fell by over 9%, or at an annualized rate of about 34%. Policymakers were quick to respond with expanded unemployment insurance, aid to state and local governments (so that they didn’t have to cut their spending like they did during the Great Recession), grants and tax breaks for small businesses, and perhaps most significantly, stimulus checks sent to over 100 million households, totaling thousands of dollars each. Since these were mostly spending measures, they were supported more by Democrats than by Republicans, although both groups recognized the severity of the problem and were largely in agreement early on. Especially during the debates over later rounds of the stimulus checks, many discussions were had over the appropriate size and target of the checks. Ultimately, compromises were made and no side got exactly what it wanted.

The conflict over which policy tool to use can be frustrating to those who want to categorize economics as “liberal” or “conservative,” or who want to use economic models to argue against their political opponents. However, advocates of smaller government, who seek to reduce taxes and government spending can use the AD AS model, as well as advocates of bigger government, who seek to raise taxes and government spending. Economic studies of specific taxing and spending programs can help inform decisions about whether the government should change taxes or spending, and in what ways. Ultimately, decisions about whether to use tax or spending mechanisms to implement macroeconomic policy is a political decision rather than a purely economic one.