Knowledge will forever govern ignorance, and a people who mean to be their own government ought to arm themselves with the power which knowledge gives. – James Madison
The opponents of a strong defense constantly complain about US defense spending and falsely portray it as “unlimited”, “huge”, “bloated”, “excessive”, “higher than during the Cold War”, and other false epithets.
They demand deep defense cuts, starting with maintaining the sequestration mechanism. They malign the DOD as profligate. They claim that the defense budget is to blame for America’s fiscal woes and that without defense cuts the federal budget won’t be balanced.
They are completely wrong, however.
The core defense budget, the FY2012 National Defense Authorization Act, is $526 bn this fiscal year. This amounts to 3.59% of America’s GDP ($14.66 trillion according to the CIA World Factbook). The total military budget (including spending on Iraq, Afghanistan, and the DOE’s defense-related programs that amount to $17 bn) is $662 bn, and even though this figure may seem huge, it is not: it equals only 4.5% of GDP, a Carteresque level of military spending. 
The FY2012 Defense Appropriations Act appropriates even less for defense: just $518 bn, an inadequate figure that amounts to just 3.53% of GDP. The total military budget it appropriates is $633 bn, i.e. 4.317% of GDP. 
Whichever figure you take for defense spending – 3.53% of GDP or 3.59% of GDP (which is a tiny difference) – this is a historically record low level of defense spending, the lowest since FY1948, excepting the late 1990s. Even if you measure total military spending, this figure is still lower than it was throughout the ENTIRE Cold War except FY1948. Even in FY1949 and during the Carter Era it was higher. In FY1949, the US spent 4.8% of its GDP on the military, and even under Jimmy Carter it was never lower than 4.6% of GDP (in FY1979). Specifically, under Carter, the figures were as follows:
Military spending did not decline below 4.5% of GDP (and later, under 4% of GDP) until the 1990s, when the US unilaterally disarmed itself. It fell to 4.4% of GDP in FY1993 and 4% in FY1994, and then fell further, bottoming out at 3.0% of GDP in FY1999-FY2001.
Defense spending, and even total military spending, is also at a historically low ebb as a part of the total federal budget. Under President Eisenhower, the absolute majority of it was spent on defense. Presidents Kennedy and Johnson devoted 46%-49% to that purpose. President Nixon devoted 30% in FY1971. President Reagan spent 24%-26% of the total federal budget on defense during his time. Now the total military budget amounts to just 19% of the total federal budget. The core defense budget equals just 14% of that.
Another measure with which defense spending can be measured is spending per capita. By this measure, too, defense spending is at a historically low ebb. Ronald Reagan’s largest defense budget was that for FY1987 – $606 bn. It amounted to $2,443 per every man, woman, and child in the US (as of the 1990 census three years later, America’s population was 248 million people). This fiscal year the total military budget amounts to $662 bn, but the United States’ population is 308 million people, so it amounts to just $2,149 per one American. The core defense budget, $526 bn, amounts to just $1,707 for one American. So the burden of military spending on the average US citizen (and the average taxpayer) is small.
So, contrary to the false claims that the defense budget (or even the total military budget) is “unlimited” or “bloated”, it is not. On the contrary, it’s at a historically low ebb – whether measured as a percentage of GDP, a share of the federal budget, or the burden on the average American citizen and taxpayer.