Budget deficits today will tend to lower the rate of growth in the economy in the future. Budget deficits result in higher rates of public debt. While the U.S. borrows at very low rates, it nevertheless must pay interest on its debt, and it is that interest that represents a burden on future growth. What happens is that future tax receipts must be used to pay interest and principle on debt created by today's deficits, instead of being invested back into the country in the future. Thus, while running a deficit may create positive economic growth today, it does work to constrain future growth, but placing constraints on the amount of future national income that can be dedicated to growth in the future.
The reasons for the budget deficit definitely matter. As with any spending, there is a difference between spending on things that will build revenue growth for the future and investing in things that will not contribute to such growth (Auerbach & Gale, 2009). For example, investments in education and infrastructure will contribute to future growth, because better infrastructure and smarter people are capable of higher levels of productivity and efficiency. A nation's capital includes all of its resources, so in general any investment on the part of government that either improves the quality of those resources (e.g. education) or the ability of people within the economy to access those resources (e.g. improved transportation infrastructure) is an investment that contributes to future growth. Thus, the investment made today has a payoff in the future. As with any debt, if the debt taken today can be paid off using the proceeds of today's investment, then the debt is going to be worthwhile.
By contrast, spending that does not contribute to future growth -- such as the proverbial $2,000 toilet seat -- is not beneficial to the economy in the long run. In general, any debt that does is not invested in something that will have a payoff greater than the cost of the debt is not worthwhile. Thus, if a government needs to spend money on projects that will have a future payoff greater than the cost of that debt, otherwise the debt is unwise. So it definitely makes a difference what the deficit spending is spent on.
As an example, increased spending on job-training programs should have some positive effect, because it improves the quality of the nation's human resources. What is less certain is whether this investment pays for itself. That would depend on the interest rate on the debt, the quality of the job training and the employability of the people in the program. If the majority of participants can be converted by unemployed people receiving social services to productive taxpayers, chances are that the job-training program will be a good investment of deficit spending.
The defense budget is always a little bit contentious with respect to its merits as an investment. Certainly, there are some good investments. Most defense jobs are for Americans, both in the active military and among military contractors. Many defense jobs are well-paying, due to the amount of engineering work on building military hardware and the emphasis on information systems in modern defense. In creating so many well-paying jobs, the federal government is not only creating such direct employment, but there is also considerable indirect employment created as well, because those well-paying jobs support entire communities' worth of service industries.
In addition, defense spending has led to considerable innovation, which improves the multiplier effect for defense spending significantly. Silicon Valley, which is the global hub of the information age, began with engineers working on defense projects. The Internet, aerospace and other hardware and information systems industries were spawned by federal defense spending. Technologies developed by DoD contractors are repurposed for commercial uses. Even the automobile and steelmaking industries benefitted significantly from World War Two-era defense spending, and emerged from the war as world leaders in their respective fields. While there might be some wasteful spending on defense, and there is definitely some spending on national security interests that is not evaluated on strictly economic terms, it is likely that on balance, defense spending is a net positive for the economy.
Tax policy is one of the more contentious forms of fiscal policy, especially with respect to its benefits. Deficits spending for tax breaks is only useful if those tax…