PPBE Budgeting System Cannot Fund Emerging Tech on Relevant Timelines

The Planning, Programming, Budgeting, and Execution (PPBE) system requires the DoD to plan its budget 2-3 years before funds are available and obligate most funds within fixed fiscal year windows. A technology opportunity that emerges in March 2025 cannot receive funding until the FY2028 budget at the earliest — and that is only if a service prioritizes it in its Program Objective Memorandum (POM) build, which happens once per year. By the time money is available, the technology window may have closed, a competitor may have fielded it first, or the startup that developed it may have gone bankrupt. This budgeting rigidity is the single largest structural barrier to DoD technology adoption. Every other reform — OTA contracts, DIU prototyping, SBIR transitions — eventually hits the PPBE wall. A program manager who wants to buy a proven commercial AI system today cannot do so because their budget line funds a different capability and reprogramming requires congressional notification for any amount over $20 million. The reprogramming process itself takes 6-12 months and is limited to a small percentage of each appropriation. The net effect is that the DoD's budget is a snapshot of priorities from 3 years ago, not a response to current threats. PPBE persists because it serves Congress's constitutional power of the purse. Congressional appropriators want to control how every dollar is spent, and PPBE gives them that control through detailed budget line items and strict rules about moving money between accounts. The defense committees' staffs — who are the real power behind military budgeting — have built their expertise around PPBE and resist changes that would reduce their oversight granularity. The system also benefits the services' programming shops (N81, A8, AF/A8), which derive institutional power from controlling the POM process. The Section 809 Panel, the PPBE Reform Commission (established by FY2022 NDAA), and numerous defense analysts have recommended fundamental PPBE reform. The PPBE Commission's 2024 report proposed shifting to portfolio-based budgeting with more reprogramming flexibility, but implementation requires Congress to voluntarily cede appropriation-level control — something appropriators have historically refused to do. The few workarounds that exist (rapid acquisition funds, Commander's Emergency Response Program-style authorities) are small, temporary, and constantly at risk of being clawed back by appropriators who view them as end-runs around congressional oversight.