Amid a government shutdown that has stalled much of Congress’s agenda, the U.S. Senate managed to pass its version of the National Defense Authorization Act (NDAA) for Fiscal Year 2026 on Oct. 9 with a vote of 77-20.
The legislation moved forward after senators agreed to vote on 17 standalone amendments, while 48 other provisions were bundled into a manager’s package and adopted by voice vote.
The House passed its version of the annual defense policy bill last month in a 231-196 vote.
The Senate’s action enables the House and Senate Armed Services Committees to begin the conference process to reconcile their respective versions of the bill. However, the House and Senate versions diverge significantly in both scope and substance.
The House NDAA closely aligns with the Department of Defense (DOD) – which the Trump administration has rebranded as the Department of War – requested top-line of $848 billion, while the Senate’s version calls for $913.9 billion, creating a $32 billion gap in defense spending that will loom large in negotiations.
A major priority for both chambers is sweeping acquisition reforms, but their approaches vary. The Senate prioritizes top-level strategic shifts and legislative overhauls in how the DOD does business, while the House emphasizes procedural efficiency, including the launch of a new pilot under U.S. Special Operations Command to accelerate deployment of innovative technologies. The House also proposes the BOOST program within the Defense Innovation Unit to fast-track promising commercial tech into military use.
Cybersecurity and artificial intelligence are also central in both versions, but the Senate takes a more structural approach, designating an assistant secretary of defense for cyber policy, mandating AI security frameworks, and supporting innovation through “sandbox” testing environments.
In contrast, the House version focuses on operational execution, requiring better certification processes, increased cyber training, and launching up to 12 generative AI pilot projects. It also mandates the inclusion of a software bill of materials for all AI systems to track vulnerabilities more effectively.
Drone threats are another area of concern in both bills, though their responses differ.
The Senate shifts the responsibility for small unmanned aerial systems (UAS) from the Army to the under secretary of defense for acquisition and sustainment and mandates pilot programs to identify capability gaps. The House codifies the Joint Counter-Small UAS Office as the DOD’s lead agency on the issue and proposes integrating civilian sensor networks into base defense systems as part of a new pilot program.
The Senate version includes a notable provision protecting critical military spectrum bands through 2034, barring changes to systems operating in the 3.1–3.45 GHz and 7.4–8.4 GHz ranges without high-level certification. These frequencies are vital to radar and missile defense functions and are not addressed in the House bill.
Despite these differences, there are some areas of agreement.
Both versions support the Golden Dome missile defense system, call for updates to national missile defense policy, and emphasize the development of hypersonic weapons and telemetry vessels to improve testing.
With both chambers now having passed their respective NDAA bills, lawmakers will begin the conference process to negotiate a final version. The challenge ahead lies not only in reconciling policy differences but also in aligning on funding levels and priorities in a year where even keeping the government open has proven difficult.