Politicians and generals frequently tell Americans that our military is “the finest fighting force the world has ever known.” The Romans and Mongols might have taken issue with that, but we do have an unparalleled ability to project power around the globe and win tactical engagements, regardless of the troubling results of our post-9/11 wars. Our military, however, has an enormous Achilles’ heel: its all-volunteer manpower system.

The bipartisan, congressionally-appointed National Defense Strategy Commission recently published its consensus report on the state of the U.S. military and its ability to meet the Trump administration’s National Defense Strategy (NDS). For the first time since the Cold War, the NDS focuses on the challenges of defeating near-peer competitors such as Russia or China. The report detailed many shortcomings, including the “secular decline” in the ability and propensity of Americans to serve in uniform. This shrinking manpower pool puts U.S. national security at long-term risk, the commission says, requiring the military and Congress to take “creative steps” to address the issue.

Although welcome, this acknowledgement of reality does not go nearly far enough. Military recruiting is approaching a crisis, with clear implications for U.S. national security. The unfitness and unwillingness of American youth to serve show us the inherent limits of our current military manning. America’s vaunted all-volunteer force (AVF) is increasingly unsustainable.

The root of the problem is the fundamental math of the all-volunteer force: the “AVF arithmetic.” More than 4 million Americans turn 18 every year, but only 29 percent of them can meet minimum enlistment standards, leaving 1.2 million qualified to serve. Of those, only 15 percent exhibit any interest in military service, leaving 180,000 qualified and willing. To meet its needs, the military must recruit upwards of 85 percent of this group every year.

When the numbers grow tight (during periods of low unemployment, for example, or the grinding years of the Iraq war), the military lowers its standards (permitting felons and high school dropouts to join), offers high retention bonuses (some reaching six figures), and even forbids servicemen and women from leaving the military by using “stop-loss” orders. Maj. Gen. Malcolm Frost, commander of the Army’s Initial Military Training Command, put it bluntly: “The next existential threat we have … is the inability to man our military.”

It is an open secret in the defense community that any war with a major power such as Russia or China would require quickly restoring the draft — a possibility about which many Americans are oblivious.

Attempting to man the force from this shrunken pool has required the military (and the Army especially) to routinely resort to serious measures. Last year, the Army failed to achieve its enlistment goal for the first time since 2005 despite lowering standards, granting waivers (for mental, physical and criminal records), enlisting Category Four (CAT IV) applicants who score between the 10th and 31st percentile on aptitude tests, offering two-year enlistments, and providing student loan repayment programs.

In addition, the Army offered an individual enlistment bonus of up to $40,000 and paid an estimated $600 million in enlistment bonuses in fiscal year 2018. To gin up interest, more than 9,600 high-performing soldiers (mostly noncommissioned officers) are assigned to the Army Recruiting Command, the equivalent of three combat brigades. The Army has proposed adding 650 more this year.

Because of recruiting struggles, the Army increasingly relies on retaining more soldiers to meet its needs. The same soldiers thus make more and more deployments, associated with higher rates of traumatic brain injuries, PTSD, divorce, domestic violence and even suicide. The military’s higher compensation, benefits and enlistment/retention bonuses are disproportionately attractive to the lower socioeconomic classes of our population.

Moreover, between the difficulty of recruiting and congressionally-mandated caps on manpower, the military increasingly relies on contractors to fill as many roles as possible, another factor driving up cost but also subtly increasing risk: it isn’t clear that contractors (many of whom are not Americans) can be persuaded to provide services on a “hot” battlefield in a major war. The net effect is also to create a widening civil-military gap. Many Americans do not know someone serving in the military, and a small portion of the country bears the burdens of war.

As the commission’s report emphasizes, this is not a problem the military likely can spend its way out of. Personnel costs have skyrocketed since 2001, rising more than 50 percent in real terms. The Center for Strategic and Budgetary Assessments has reported that if personnel costs continue to grow at the current rate, and the overall defense budget remains flat, military personnel costs will consume the entire defense budget by 2039. Given America’s national debt, aging population, rising health care costs and massive unfunded pension liabilities, it is unlikely that the defense budget has much room to grow.

Perhaps the strongest evidence that the all-volunteer force is not sustainable is that it could barely be sustained during the post-9/11 global war on terror. Now, with the AVF struggling just to tread water during an era of low-intensity operations, an initial bloody nose attack during a future major conflict could prove far more dangerous than it did in World War II or Korea.

Our increasingly hollow all-volunteer military is facing renewed major threats on the horizon. Rogue states such as Iran and North Korea possess significant capabilities and have the strategic depth to make any conflict extremely painful for the United States. China is ascendant in the Pacific and assertive throughout what it sees as its sphere of influence. Russia seems inclined towards dangerous geopolitical gambles that could spark war with NATO. What limited glimpses we have of 21st century high-intensity combat indicate it will be just as bloody as past warfare.

When our next major war comes, it is almost certain to bring casualties that will overwhelm our military’s manpower reserves. Even without such a dire event, any number of contingencies could crash us on the shoals of the AVF arithmetic. Our nation’s leaders must expand the means for manning the military — or contract the ends expected of our forces — while the choice is still ours to make.

Maj. Gen. Dennis Laich retired from the U.S. Army in 2006 after more than 35 years of service.

Jonathan Askonas is a research fellow at the Center for the Study of Statesmanship at the Catholic University of America.

Gil Barndollar is the military fellow-in-residence at the Center for the Study of Statesmanship and served as a U.S. Marine infantry officer from 2009 to 2016.

[Article originally published in The Hill on December 6, 2018.]