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There is no denying that Marines must be proficient in their military occupational specialties. When a company command or deployment opportunity is presented, you should not hesitate to say, “Put me in, coach.”

Brig. Gen. Lori Reynolds, while speaking to the NCAA women’s basketball coaches during the 2013 Women’s Basketball Conference and Final Four, said, “Don’t worry about being the best on the team, be the best at your position.”

Being proficient is not the problem for low-density, staff-oriented military occupational specialty Marine officers. In fact, more often than not, you as an officer must be proficient out of necessity, because you are the only subject-matter expert available.

Being the only expert is a pitfall of being a single-dimensional staff officer. For as rewarding as it can feel to be a unit’s go-to Marine, in doing that, you can become irreplaceable in a way that hinders you from moving up. If you are so relied upon that in your absence your superiors and subordinates alike cannot effectively problem solve in furtherance of the mission, then your presence will be tirelessly required, thereby holding you to that position. There is an adage that the best offense is a good defense. Marines further learn in warfighting that the best defense is a defense with depth. Low-density, military occupational specialty Marine officers need to apply this thinking to their respective specialties. They must become replaceable.

Growing subordinate capabilities, creating comprehensive standard operating practices, developing air-tight and transparent internal control procedures, and making sure reporting seniors are familiar with billet requirements and the functions of your shop are all practices that will set the conditions for being replaceable. It is a testament to your leadership if your Marines or your replacement can carry out the mission in your absence, but it takes preparation and humility to get there.

If you are replaceable, then your command can avail you to opportunities like command and deployment. When a billet, like headquarters company commander, opens up and you’re qualified and replaceable, you stand a better chance of competing for the billet than hearing, “Sorry, adjutant, I can’t have you running around playing company commander, we need you in the S-1,” from your battalion executive officer.

The same can be said for individual augmentee deployments: If the Marines in the command are enabled to accomplish the mission in your absence, then you can throw your name in the hat to be considered, instead of being told, “Sorry adjutant, there is only one of you. The unit needs you here, not filling some individual augmentation anyone can do.”

In a low-density, military occupational specialty where command is not typically in the career path, breaking out of the staff track is very challenging despite the Marine officer’s ability to lead. For a Marine officer in this position to create career options beyond staff billets, you must be a replaceable, well-rounded officer, and must seek non-military occupational specialty opportunities or B-billets.

In reference to being a long-distance runner, a flag officer once told me, “You can’t be a one-dimensional athlete.”

His cautionary advice was related to fitness in that as an athlete, you should seek to be strong all-around, not just at one activity; his advice is applicable to career officers’ development as well. Proficiency in your military occupational specialty alone will leave you one-dimensional as an officer, lacking the well-roundedness required for growth as a leader and officer.  

From The Basic School through every other officer schoolhouse, becoming a well-rounded Marine Air-Ground Task Force officer is the hallmark phase bestowed to each pupil. For the second lieutenant through captain ranks, well-roundedness comes from understanding how your specialty and unit fit into the bigger picture.

Junior officers can expound on that understanding by taking the time to learn the purpose and application of their peers’ military occupational specialties. For example, a fiscal officer or adjutant doesn’t need to know how to fly an F/A-18D, but when stationed with the wing should take the time to learn how sections, divisions, and squadrons deploy and are employed.

In addition to learning from peers within your own unit, well-roundedness comes from education resident, non-resident, and personal education alike. If you’re content to just check the box on having your non-resident professional military education complete, then be prepared for the anemic professional development that follows. Required professional military education is just the tip of the learning iceberg.

Learning to be a critical thinker is a continuous process, fed by professional military education, professional discourse, experience, and reading- lots of reading. The foundation for critical thinking is understanding how the Marine Air-Ground Task Force works. More importantly, Marine officers need to grasp why the Corps fights as a Marine Air Ground Task Force and the ability to conduct forcible amphibious operations and sustained combined arms land operations across the range of military operations.

Marine officers comprehension cannot be limited to the way military occupational specialty fits into the task force. Military occupational specialty proficiency — combined with task force comprehension and robust reading on current events, history, doctrine, and theory — will support a staff officer becoming a valuable member of the staff. Knowledge beyond specific subject-matter expertise will earn that officer a seat at the table when it comes to operational planning.

The importance of choosing a competitive B-billet as a low-density military occupational specialty Marine officer was best expressed to me by a mentor who said, “On a staff, you are always one of one; you are always compared to Marines of the same rank, but none of them are ever filling the same billet with the same tasks. You need to be able to show the Marine Corps that you can excel when you have the same mission as your peers.”

Looking for ways to grow as an officer outside of your military occupational specialty is critical for being placed in billets of greater responsibility and command.

Excelling in a B-billet demonstrates your ability to think critically in an area where you are not a subject-matter expert, showing you are comfortable with being uncomfortable. Serving in a B-billet that requires leading many, as opposed to a staff assignment leading few, also demonstrates your leadership potential.

Billets like officer selection officer, recruiting station executive officer, or operations officer, Marine officer instructor, series commander, and Marine security guard area officer are competitive on varying levels, but all demonstrate your ability to lead and perform outside of your military occupational specialty.

In contrast to supporting establishment B-billets where you are leading few, if any, Marines and schoolhouse B-billets where you are completely within your military occupational specialty, B-billets on recruiting duty, the drill field, college campuses, and spanning embassies offer greater leadership responsibilities and mission requirements beyond the scope of a primary military occupational specialty. For example, officer selection officers in a district with 11 officer selection stations and 11 or 12 different officers will each have the same or similar missions and start on equal playing fields to accomplish the mission.

Success is quantifiable in terms of mission making, and each officer selection officer is left to be his or her own current operations officer, future operations officer, logistics officer, and administrator. With a school-based foundation in systematic recruiting, the officer is left to sink or swim. To succeeds you must demonstrate that you are capable beyond your military occupational specialty.

To breach the staff-oriented billets barrier, low-density military occupational specialty Marine officers should look for opportunities to command and deploy. If you’ve made yourself replaceable, identified yourself as a well-rounded Marine Air-Ground Task Force officer, and succeeded in a defining B-billet, you must be clear that you want the opportunity for greater responsibility.  

During initial counseling with a reporting senior, a Marine officer from a low-density military occupational specialty should indicate the desire to be considered should command, deployment, or greater responsibility opportunities arise.

Break out of the pack or be prepared to stay a staff officer your entire career.