The budget deal signed earlier this month by President Trump provides additional money for a military in desperate need of rebuilding. The funding boost will help fill critical shortages, replace worn-out equipment and train formations.

But money can’t fix one of America’s greatest security challenges: The reality that fully 71 percent of the country’s youth can’t qualify to join the military. Even the best planes, ships and tanks can’t avail without enough qualified volunteers to fill the ranks.

What disqualifies so many from serving? For some, it’s the lack of a high-school degree. For others, an extensive criminal record. But the biggest obstacle of all is poor health and fitness.

It’s not that the fitness standards are overly strict. Recruits don’t have to be lean, mean fighting machines to enlist. But they can’t be obese or suffering from a significant chronic health issue.

Over half of all Americans aged 17-24 have disqualifying weight or chronic health issues. Yes, the military takes pride in transforming volunteers into the best versions of themselves. But allowing obese or unhealthy Americans to enlist places them at a much higher risk of injury. A recent study published in the Journal of Public Health Management & Practice found a direct correlation between injury rates in Army basic training and the recruits’ physical fitness at the time they entered service.

This is a problem reflective of American society. One in three adults and one in five kids are obese; 91 percent of our children live on a poor diet; and one-quarter of our youth spend three or more hours per day watching TV.

We often debate the validity of claims of American “exceptionalism,” the belief that the U.S. is special. In one area, however, that debate is settled: the U.S. is by far the fattest country in the world, with a whopping 38.2 percent obesity rate. Mexico, at 32.5 percent, is a distant second.

National security requires that our armed forces be able to recruit as many Americans as are needed to fulfill their missions. Today, serious threats to our security may be found all around the world, making the need for a capable and lethal force as important as ever.

Some have suggested enlisting illegal immigrants to fill the ranks, offering them the promise of citizenship in exchange for their service. Overlooking the challenges of conducting background checks on this population, what type of statement does it make when we cannot find sufficient number of qualified volunteers among an overall population of 323 million that we must resort, effectively, to foreign mercenaries to defend our country?

So what can we do to address the problem of rampant physical unfitness? Few tools present themselves at the national level, but one thing the president could do — and do quickly — is to appoint motivated and prominent Americans to serve on his Council on Fitness, Sports and Nutrition. These council members would not only give him advice on this issue, they would serve as role models for young Americans.

Despite the complex nature of the problem, glimmers of solutions are visible elsewhere, in our states, towns, cities and schools.

Consider Kearney, Nebraska. Public schools there integrated physical activity into daily school life as well as before- and after-school programs. Since implementing the program, the obesity rate among children in grades K-5 has declined 13.4 percent.

Another noteworthy initiative is the U.S. Soccer Foundation’s “Soccer for Success” program. It serves a population of 40,000 at-risk youngsters in over 30 cities Ninety percent of the kids who were overweight or obese when they entered the program improved or maintained their body-mass-index while participating in the program.

Concerted action can go a long way toward solving our nation’s growing fitness problem. This is about far more than appearance, self-image or even personal health. Today it is a looming national security crisis.