The Common Core is a set of national standards dictating what students should be taught in school — and lots of people hate it.

But how can you hate something that benefits military families and aids national security? At least, that's the gist of what the Center for American Progress Action Fund has told us: “Close to 75 percent of Americans between the ages of 17 and 24 are not qualified to join the military,” and "national standards will help our service families," and “raising standards and academic achievement is a national security imperative.”

Thing is, the Army has in the past year rolled out more stringent guidelines for tattoos, body fat, and what enlisted soldiers must accomplish if they wish to become officers.

So here's a Common Core–worthy question: How can it be that America’s youth are so ill-prepared by school that their inability to qualify for military service is a national security issue, and that the Army can afford to turn away otherwise qualified people because they have some ill-advised ink on their forearms?

The answer is that the notion of a military decimated by recruiting shortfalls due to a generation of kids who are unfit for military service is a crock. The military rejects a lot of would-be recruits not because the recruits are lousy, but because the military can currently afford to be picky — their recruiting needs amount to less than 2 percent of new high school graduates. And with a job market that continues to be pretty terrible, the military is getting enough interested kids that it can weed out some of them based on things like face tattoos and big guts.

The group arguing loudest about the fact that dumb kids are ruining our national security is, it turns out, made up of retired military personnel. Their group, Mission: Readiness, often gets cranky about their being too few kids fit for war; in the past, it has used the notion that high ineligibility numbers pose a threat to military readiness to make the case for junk food bans and universal preschool.

A 2010 report by Mission: Readiness was covered in a breathless Huffington Post article entitled “SHOCKING: Nearly 1 In 4 High School Graduates Can't Pass Military Entrance Exam” that was recently linked to by Vox. But here is what none of them seemed to understand about what's being referred to as the “military entrance exam”: It is population-normed, meaning that the military didn’t set the standard based on academic requirements.

Here’s another thing you should know about the AFQT: The material it encompasses is already part of elementary school and high school curricula everywhere.

Instead, the military set the standard based explicitly on a desire to disqualify a certain percentage of America's youth. A score on the portion that determines eligibility to serve, referred to as the Armed Forces Qualification Test (AFQT), is in the form of a percentile that tells the candidate how he or she did compared to a representative sample of his or her peers. In other words, if you can’t score at least a 31 — meaning that you scored as well as or better than 31 percent of the sample — the Army doesn’t want you.

The scoring system is periodically re-normed based on how American youth perform. So if, as they say they do, Mission:Readiness wants a higher percentage of American high school graduates to pass the test, the only options are to reduce the proportion of high school dropouts who pass the test, or to reduce the proportion of Americans who graduate from high school.

Also, to the extent that we’ve seen changes in absolute performance among test takers, they’ve actually been positive: The last time the Department of Defense re-normed the scores, it was to slightly raise the absolute performance necessary for eligibility because American youth were scoring so well.

Here’s another thing you should know about the AFQT: The material it encompasses is already part of elementary school and high school curricula everywhere. The math questions cover arithmetic, along with some algebra and geometry. The reading sections address basic vocabulary and reading comprehension. Sure, many high school graduates unfortunately struggle with this relatively basic material, but it’s not for lack of standards.

And how is the military doing in terms of recruiting? In the last fiscal year, recruiting goals were at less than 50,000 — this at a time when there were about 3.2 million new high school graduates. In other words, the military's recruiting goals were met.

With the number of qualified youth vastly outstripping the military’s demand, the issue — even in years in which recruiting goals are much higher — isn’t whether there are enough qualified youth out there, because there are way more than enough. The issue is what the military can and must do in order to make itself attractive relative to colleges and other employers.

While older Americans can no doubt agree that it would be nice if America’s youth were better in various ways — and also turned down their damned music! — America’s youth no doubt would agree that it would be nice if old people laid off once in awhile. Neither of those things is probably going to happen. Regardless, the military will continue to do just fine.