Roger Staubach won a Heisman Trophy at Navy, and then served a tour in Vietnam before playing in the NFL. (ASSOCIATED PRESS)

Football players at Army, Navy and Air Force should be no less committed to their duty than, say, Prince Harry. That appears to be the reasonable position of Defense Secretary Jim Mattis, who has issued a new order blocking military academy athletes from entering pro drafts straight out of school. But Mattis is only half-right. He would be even more right to demand full terms of active service from them, without exception. No more class pets.

Apparently admirals and generals can be as prone to athlete worship as the average college booster. The various military branches have been increasingly accommodating to athletes in recent years, culminating in a 2016 policy from the Defense Department that would have let academy prospects defer their service if they have a shot at the NFL or any other major league. A memo from Mattis canceling that policy Monday only partly restores the starch. Curiously, Mattis left in place a far more objectionable policy, one dating from 2008 that allows athletes to serve just two years of active duty, if they’re talented enough, while others serve five.

The DOD’s rationale for this: “Exceptional personnel with unique talents and abilities may be released . . . when there is a strong expectation they will provide the Department with significant favorable media exposure likely to enhance national recruiting or public affairs efforts.”

This is nothing more than a huge back-bending rationale, born of a need to excuse our captivation with games and great athletes. You can tell that it’s nothing more than permission for an indulgence, because it’s so inherently self-contradictory. Joe Ruzicka, a retired Naval officer and former legislative fellow for Sen. John McCain, points out: If athletes are so vital to “national recruiting or public affairs,” then “why make them serve immediately during their most valuable playing time?” Why deprive them of their prime in the spotlight? “The timing is off,” Ruzicka said.

But most importantly, why is there any option at all “to serve less than one’s full-service obligation?” asked Ruzicka, who graduated from the Naval Academy and put in more than 2,000 hours flying F-14 Tomcats and F/A-18 Hornets.

Ruzicka has a better idea: Let them play pro ball first, and then fulfill their active duty commitment — all of it.

Roger Staubach did a tour in Vietnam after winning the 1963 Heisman Trophy at the Naval Academy, and he didn’t enter the NFL until he was a 27-year-old rookie. But that uncompromising service policy weakened in more recent years, after the Navy negotiated ways to allow Napoleon McCallum to play for the Los Angeles Raiders while stationed at a naval base in California, and David Robinson to enter the NBA while in the civil engineering corps. Since then, inconsistency has followed on uncertainty.

“We’ve gone back and forth on this for 10 years or more,” Ruzicka said. “It’s not fair to athletes. The process is flawed, and it’s not equitable across the services.”

The current policy allows each service branch to decide whether an athlete-applicant gets an opt-out, and the results have been uneven. Jalen Robinette, Air Force’s career leading receiver, spent this year focusing on his prospects in the NFL draft rather than active duty, only to learn at the last minute he was ineligible thanks to the policy reversal. Navy running back Eric Kettani (class of 2009) was granted a release after two years to play for the Patriots. Navy pitcher Mitch Harris was drafted by the St. Louis Cardinals in 2008, only to serve a full four years and eight months in 30 countries. And of course Navy grad Billy Hurley III did five years as surface warfare officer driving destroyers before he made it to the PGA Tour, and played in this year’s Masters.

Why not flip the order? Let them play first, and then serve? Write a policy that allows for a delayed-entry option, in which athletes can serve in the reserves while playing, but require them to serve out their full active-duty obligation as officers when their sports career is over. “It would be a win-win,” Ruzicka said. The athlete would get a shot at a career; the service would get their valuable ambassadors, and full tours of duty.

“You don’t go to an academy because you want to play football; you go because you want to serve,” Ruzicka said. “You’re just switching the commitment around.”

This would do three things at once. It would remove the perception of preferential treatment and assignments. It would satisfy our taxpayer investment and the military’s investment in training. And it would allow these highly aspirational people to explore their full physical capabilities, while also satisfying the instinct to serve that led them to the academies in the first place, removing the tension between the two.

The average pro athlete’s career is ephemeral. The NFL player tends to last somewhere between 3.5 to six years; the NBAer around 4.6 years; and in Major League Baseball, 5.6. Most athletes’ careers would in all likelihood be over long before they reach the age of 30, which is still below the maximum enlistment and commissioning ages for most service branches. An example such as Robinson, who played to 37, is extremely rare, but still wouldn’t preclude active service.

It’s a timelessly interesting question whether competitive character on the sports field translates to real leadership. There may well be some correlation between the “friendly fields of strife” and developing certain military aptitudes. In 1912, Army had no fewer than nine future generals on its football squad, including Dwight Eisenhower and Omar Bradley. Still, the service academies always have been self-aware enough to be wary of their fixations with sports, particularly football. West Point’s 1912 class yearbook, The Howitzer, cautioned the cadet corps: “Football is not life and death. Football is sport. Sport is chance.” It’s a critical distinction.

Officer training is all about reducing chance with expertise and organization, so as to minimize blood sacrifice. No substitute for this training exists; football or baseball is mere shadow theater compared to it. Presumably this is why Mattis made the decision he did: to stress the order of priority. “The military academies and ROTC exist to develop future officers who enhance the readiness and lethality of our military services,” he said. He believes that allowing athletes to enter drafts straight out of the academies would undercut that priority. But why wouldn’t demanding an eventual full service commitment be a better way to emphasize that priority than giving them special opt-outs after two years?

Just as there is no game that approximates war, there is simply no equitable exchange for active duty. No amount of recruiting or goodwill touring makes for a fair exchange. Not even close.

For more by Sally Jenkins, visit washingtonpost.com/jenkins.