Since World War II, the United States has been the world’s largest defense spender by far. US wars in Iraq and Afghanistan in the past decade accelerated spending, driving it to historic heights and increasing America’s global share of a $1.55 trillion market to 44 percent—more than six times the share of China, the second-leading spender.1 1.Stockholm International Peace Research Institute,

Today, the defense budget is set to decline dramatically. That’s not unusual. In 1952, defense spending reached a post–World War II high of 15 percent of GDP. In the years after the Korean War, it fell by 45 percent. In the 1970s, following the end of the Vietnam War, total defense spending fell by 33 percent; again in the 1990s, as the Cold War came to a close, defense spending declined by 35 percent. All of these cuts were deeper than those currently planned. Another similarity is that each of those cuts came at the end of a major conflict.

Meanwhile, the long-term trend line has been remarkably stable. America’s dominant position in the defense-spending-league table since the end of the Cold War reflects the country’s economic strength as much as its policy stance and external orientation. In the short term, the country adjusts its defense spending to reflect the threat level, but over the longer term, it has the defense forces it can afford.

Today’s belt-tightening may seem uniquely difficult, with defense budgets forced to be reduced even as major conflicts continue to erupt. Yet it’s worth being reminded of Rudyard Kipling’s timeless military principle, laid out in 1886 in “Arithmetic on the Frontier”:

No proposition Euclid wrote,
No formulae the text-books know,
Will turn the bullet from your coat,
Or ward the tulwar’s downward blow.
Strike hard who cares—shoot straight who can—
The odds are on the cheaper man.