Practice Notes

Where Have All the Sergeant Cullins Gone? Future Innovation at the Tactical Level

By Colonel Ryan W. Leary

Article published on: May 30, 2025 in the Army Lawyer issue 1 2025 Edition

Read Time: < 10 mins

A “Rhino Tank,” modified with SGT Cullin’s solution to cut through the hedgerows of Eastern France during World War II. (Source: Normandy Archives)

In 1944, shortly after the successful invasion of Western Europe, the Army had a capability gap that threatened to slow the advance of forces deeper into Europe and potentially weaken the D-Day momentum enjoyed by Allied forces. ¹ Our Army could not rapidly transit tanks through hedgerows, pervasive throughout Eastern France, without either canalizing forces to road networks or exposing the vulnerable tank underbelly to enemy forces. ² Sergeant (SGT) Curtis Cullin famously developed an innovative solution to this problem; he repurposed scrap steel from German roadblocks and affixed steel prongs on the front of U.S. tanks, which enabled tanks to easily cut through hedgerows and support infantry advances into the interior of France. ³ When General Omar Bradly witnessed these “Rhino Tanks” in action, he ordered a full-scale retrofitting of the majority of tanks in the First Army in advance of Operation Cobra. ⁴

To be fully prepared for our next conflict against a near-peer adversary in a multi-domain environment, we must be agile enough to innovate on two levels; we must conduct large end-item innovation at the strategic level and iterative, fast-paced innovation at the tactical level to fill smaller capability gaps that could give our force the edge on the battlefield. ⁵ As we prepare for the next conflict, a question to consider is whether we have the authority to enable a modern-day SGT Cullin—to solve capability gaps at the tactical level and elevate those innovations to strategic leaders who can magnify the impact of those innovative solutions, at scale, across the force. This article briefly highlights the necessity of pushing research, development, testing, and evaluation (RDT&E) authority and funding sources to the tactical level. It then proposes potential enabling solutions that would provide a pathway for tactical-level innovation.

Why Innovate at the Tactical Level?

With the advent of multi-domain operations and the resurgence of major nation-states competing on the global stage, identifying capability gaps and developing innovative solutions to maintain a competitive advantage will be critical to success during both the competition stage and armed conflict. ⁶ Further, by demonstrating our adaptability and the cost of engaging in combat with our joint force, we may be able to deter future conflict with our near-peer adversaries. ⁷ While innovation across major combat and communications systems will be key to successful competition, to reduce the risk of vulnerability, we must also be able to assess shortcomings by employing existing and future systems well below the strategic level.

Leaders at the operational and tactical levels recognize this requirement, are developing an innovative culture, and are placing a premium on a Soldier’s ability to find innovative solutions at the tactical level. ⁸ During my service as the staff judge advocate at the 101st Airborne Division (Air Assault), the division commander drove innovation by standing up EagleWerx: an innovation center that partners with regional educational facilities to develop innovative solutions and affords Soldiers within the division a space to work on and cultivate ideas based on capability gaps they identify at their level. ⁹

While innovation across major combat and communications systems will be key to successful competition, to reduce the risk of vulnerability, we must also be able to assess shortcomings by employing existing and future systems well below the strategic level.

The Fiscal Authority Problem

In our current scheme of laws and authorities, commanders at the tactical level lack the authority to pursue innovative solutions beyond the initial identification of a capability gap. More specifically, under fiscal law provisions, agencies may only spend appropriations for purposes Congress specifically designates. ¹⁰ While the operations and maintenance (O&M) appropriation provides seemingly broad authority to expend funds, ¹¹ when a more specific appropriation exists for a particular purpose, agencies must use that appropriation. ¹² In the case of developing innovative solutions for capability gaps, the RDT&E appropriation is more focused on researching, developing, and testing those potential solutions. ¹³ It is, therefore, the proper appropriation to utilize for this purpose. The fiscal year 2024 Further Consolidated Appropriations Act states that the RDT&E funds are for “expenses necessary for basic and applied scientific research, development, test and evaluation, including maintenance, rehabilitation, lease, and operation of facilities and equipment.” ¹⁴ Therefore, after tactical-level units identify gaps in capabilities that necessitate modifications or additional development, they require a unit or level of command with access to RDT&E to support and ultimately underwrite the development or testing needed to move from the capability gap identification phase to the solution development phase.

While some tactical-level units have access to procurement authority or can conduct small-scale development, ¹⁵ most conventional units at the tactical level only have access to standard O&M funds; they would, therefore, be unable to develop any material solution to any capability gap they identify at their level.

Risk of Pushing Innovation Authority to the Tactical Level

As presented, empowering subordinate Service members and leaders to innovate and encouraging bottom-up innovation sounds like an easy win for everyone—it encourages creativity, empowers junior members of our organization to become part of the solution to challenges they see at their level, and better suits our equipment for our operational requirements. So, why not just push down that fiscal authority by allocating RDT&E funds to units across the force?

Practically speaking, broad-based innovation in the defense enterprise is extraordinarily expensive, and the RDT&E funds provided to the Department of Defense (DoD) are targeted at large-scale, systematic programs and solutions. ¹⁶ RDT&E is also a limited resource. Even though the last RDT&E appropriation provided by Congress included $17 billion for the Army, ¹⁷ when you look across priorities for modernizing the force, enabling multi-domain operations, and competing in space, it becomes clear how challenging it would be for tactical-level units to compete for resources to support an innovation that may not ultimately provide an impact that compares to those broader initiatives.

Consequently, to seed the innovation of the next SGT Cullin and to avoid missing an opportunity to fill capability gaps that could be crucial in our next conflict, we must develop a new approach that affords tactical-level innovation and development without taxing the already overburdened RDT&E system for the DoD. ¹⁸

A U.S. Soldier holds a drone during the 173rd Airborne Brigade’s Innovation Symposium as part of the inaugural Vicenza Military Community (VMC) Innovation Week hosted by U.S. Army Southern European Task Force, Africa and the 173rd Airborne Brigade at Caserma Del Din, Italy. (Credit: PFC Jamaries Casado)

Potential Solutions to the Tactical Innovation Authorities Gap

With a full appreciation for the limitations on our ability to push down RDT&E authority to conventional units below the strategic and operational level, some solutions would minimize this risk while still allowing the junior members of our organization to identify capability gaps, develop their own solutions, and potentially transmit those solutions to similar formations across the force. Two potential options would achieve these goals.

The first is to create an authority that permits O&M funding for RDT&E purposes up to a certain threshold amount, similar to how components may use O&M funds for investment items up to $350,000 under the existing expense-investment threshold. ¹⁹ The second is to budget for and provide a small amount of RDT&E at an appropriate level and encourage organizations to submit innovation proposals to receive RDT&E for particular projects.

Establish a Threshold for Using O&M to Support RDT&E Initiatives

Pursuant to the tenets of fiscal law discussed above, whereby an agency must use the most specific appropriations for expenditures that fall within that purpose, units are ordinarily required to use procurement funds to acquire investment items. ²⁰ Recognizing, however, the limited access that lower levels have to procurement resources and their need to obtain lower-cost investment items to conduct ordinary operations, Congress annually authorizes agencies to expend O&M funds for investment items whose value does not exceed $350,000. ²¹

To encourage tactical-level innovation and enable commanders to fill capability gaps that, on their face, may not seem to rise to the level appropriate for Service labs and program executive offices, Congress could authorize O&M funds, up to a certain amount, per innovation project (e.g., $500,000) and limit the total cap on this authority’s use per year (e.g., $1.5 million). This approach makes funds immediately accessible to commanders at all levels and provides a built-in cap on annual expenditures. It also incentivizes a deliberate and measured approach to innovation at the tactical level because commanders must weigh the decision to fund RDT&E projects against all other requirements funded from their base budget.

A Shark Tank ²² of Tactical-Level Innovation

The second solution—to request an additional small amount of RDT&E funding in the annual appropriation—would enable each Service to manage its portion of that funding and support the tactical-level innovations of its choice. It would not be difficult to establish a process whereby units submit their proposals or pitch them to a board of decision-makers. ²³ As mentioned above, U.S. Central Command, XVIII Airborne Corps, and 25th Infantry Division have all developed and executed similar endeavors to encourage and promote Service member innovation. ²⁴ With this new funding scheme, decision-makers running these Shark Tank-like programs could then easily provide their portion of RDT&E funding to selected projects. Similar to how General Bradley recognized how effective the Rhino Tank would be if every element in his Corps had that capability, this approach would afford strategic-level leaders to examine the impact of these innovations when distributed at scale across the force.

Conclusion

History assures us that our next conflict will not be exactly like the last. Furthermore, in large-scale combat operations in a multi-domain environment, the pace at which a joint force can adapt will be critical to achieving success. By financially empowering the innovative spirit and vision of our Soldiers and leaders at the tactical level, we can prevent the hedgerows of the next conflict from stifling our momentum on the battlefield. Whatever approach we choose to help close the capability gaps at our tactical level, we should not delay in implementation so that we can, hopefully, minimize any necessary in-stride adaptations and maximize our advantage in the next fight. TAL