Worried that double digit increases in military spending might soon come to an end, some commentators have concocted a scheme for ensuring that the nation’s defense budget never falls below a certain percentage of gross domestic product.

Former Missouri Sen. James Talent and others at the Heritage Foundation would establish “a rule that the core defense budget should never sink below 4 percent of the nation’s GDP (gross domestic product).” Gary Schmitt at the American Enterprise Institute would see Heritage’s offer and raise it to 5 percent of GDP. The editors of The Wall Street Journal recently proposed spending between 5 and 6 percent.

The overarching question for Americans should not be whether we should spend more on defense, but rather why we spend so much. Fighting wars in Iraq and Afghanistan while at the same time trying to update forces built for the Cold War have strained our military to the breaking point. Proposals to alleviate the burdens on our troops are welcome, but adopting an arbitrary floor for military spending isn’t the answer. A better approach would be to reorient our foreign policy, shed our obligations as the world’s policeman, and expect our allies to play a greater role in defending themselves.

Admittedly, portraying the Pentagon’s budget as a share of GDP has some political advantages. First of all, it appears to be a small number — just 4 percent of GDP. The 4 percent of GDP figure also looks modest when compared with other countries. Whereas no one disputes that the United States spends far more on its military than any other country on the planet (in fact more than every nation combined), many countries spend more as a percentage of their GDP. The CIA’s World Factbook finds that 27 countries spent at least as much as the United States.

A closer look at this list reveals just how misleading the statistic really is. There are a few very poor countries that spend a larger percentage of their meager GDP, but that translates to far less military capacity in real terms. Other relatively wealthy countries at the top of the list — including Oman, the United Arab Emirates, and Qatar — live in close proximity to chaos in Iraq and a resurgent Iran. It is no wonder that they might want to spend a relatively large percentage of GDP in order to provide security for their people, but they spend barely a fraction of what the United States commits to our military, a military that spends a good amount of time defending them.

But what of our prosperous allies in Europe and Asia? Japan spends about 1 percent of GDP on defense. No NATO country spends more than 3 percent of GDP, and the average expenditure among NATO member countries — excluding the United States — is a paltry 1.74 percent. What is remarkable, then, is that the United States’ considerable wealth, and our relatively advantageous geo-strategic position, should enable us to spend far less, rather than even more, on the military.

We have chosen to spend far more than others not because our own security is at stake, but rather because we fear that the world will collapse into chaos were it not for the U.S. military acting as a de facto global sheriff.

How much each American pays for this dubious privilege is easy to quantify. The sum total that we will spend this year on national defense approaches $800 billion, or approximately $2,660 for every person living in the United States. By way of comparison, the average British citizen pays just over $1,000 for defense. The average Frenchman pays around $845. Japan spends about $340 per person on defense; Germany just over $430.

Spending six times as much as Germany on a per capita basis will not bankrupt us as a nation. We could go on assuming that we have responsibility for solving all of the problems of the world. We could continue to pretend that we have an infinite reservoir of public will and public money just waiting to be tapped not only for our own defense, but also for the defense of others. But to do so would only temporarily absolve us from having to make hard choices about where we should be spending our money. And in the meantime, our troops are bearing the brunt of it.

A 4 percent floor for defense spending won’t solve this problem; a more shrewd and restrained foreign policy might.