Why Parliaments Should Become Stronger Actors in Security and Defence Policy

Security and defence policy has traditionally been regarded as a domain dominated by executives, military leaders, and diplomatic elites. Governments and presidents often justify this concentration of authority by arguing that foreign and security affairs require secrecy, speed, and coherence. Yet democratic governance demands that elected representatives maintain oversight of decisions that can involve war, military deployments, intelligence activities, and major defence expenditures. The growing literature on the ‘parliamentarisation’ of foreign and security policy highlights both the importance and the challenges of strengthening legislative control in these policy areas.

The concept of parliamentarisation refers to the increasing involvement of legislatures in shaping, scrutinising, and authorising security and defence policy decisions. While constitutional rules often grant parliaments powers over military deployments, defence budgets, and international agreements, the practical influence of legislatures varies significantly across countries. Formal rules provide the institutional foundation for oversight, but parliamentary influence also depends on government-opposition dynamics, party competition, and on the willingness of members of parliament (MP) to challenge and criticise executives. As a result, assessing legislative-executive relations requires attention not only to constitutional arrangements but also to how these arrangements operate in practice. In this sense, security and defence policy is not really that different from other policy areas, although in security issues there is often the expectation that the country ‘speaks with one voice’ – and hence parliamentary debates, where different arguments are presented publicly, can be seen as undermining the ability of executives to advance national interests. Yet, this should not be accepted as an excuse for sidelining parliaments in security matters.

A major rationale for parliamentary involvement is accountability. Security and defence policy decisions can have profound consequences, including loss of life, long-term financial commitments, and effects on international stability. Parliaments provide an arena in which governments must justify their actions publicly. Through debates, questions, committee hearings, and investigative inquiries, legislators can challenge official narratives and force executives to explain their decisions. Such scrutiny is particularly important because executives often may use securitisation strategies, presenting a particular issue as an urgent threat that requires exceptional measures. While such arguments can mobilise support, they may also weaken democratic debate by portraying dissent as irresponsible or unpatriotic. Parliamentary oversight therefore serves as a safeguard against excessive executive power.

The deployment of military forces illustrates the tension between executive discretion and democratic control. Decisions about military intervention are often made under conditions of uncertainty, yet they can involve enormous political and human costs. Research increasingly shows that such deployment decisions are not fundamentally different from domestic political conflicts. Political parties frequently hold distinct positions on military interventions, and these disagreements reflect broader ideological differences. Consequently, parliamentary debates over deployments should not be viewed as abnormal intrusions into security policymaking but as legitimate expressions of democratic contestation.

At the same time, effective oversight remains difficult. A central challenge is informational asymmetry. Executives, military officials, and intelligence agencies typically possess information unavailable to legislators. This imbalance limits the capacity of parliaments to evaluate policy choices independently. The problem is particularly acute in intelligence matters, where secrecy is often necessary but can shield intelligence agencies and the executive branch from scrutiny. Intelligence oversight committees are intended to address this challenge by granting selected legislators access to classified information. However, as a recent case study of Finland illustrates, MPs seated in intelligence oversight committees may become closely integrated into the intelligence community they are supposed to oversee. The need to maintain confidentiality and trust can reduce their willingness to challenge official assessments.

The relationship between intelligence and decision-making became especially visible in the lead-up to the 2003 Iraq War. The British government under Prime Minister Tony Blair presented in the House of Commons in September 2002 intelligence information concerning Iraq’s alleged weapons of mass destruction in an effort to justify military action. The publication of the so-called September dossier and its subsequent controversy demonstrated how intelligence can be used to legitimise policy choices. Later inquiries raised significant concerns about the interpretation and presentation of intelligence evidence. The Iraq case highlights the importance of robust parliamentary scrutiny, particularly when executives rely on secret information to build support for military interventions. Legislators must be able to assess not only policy outcomes but also the quality and reliability of the evidence used to justify decisions.

Parliamentary control extends also to defence procurement. As the on-going war of aggression in Ukraine demonstrates, modern warfare is changing and it is difficult to estimate what type of arms are needed in the future. Cost-effectiveness is a key consideration here, as purchase of military equipment such as fighter jets entails significant long-term financial commitments. Because procurement decisions can shape defence capabilities for decades, parliamentary oversight is crucial. Legislators must evaluate whether proposed acquisitions correspond with strategic needs and represent responsible use of public resources.

Another important dimension concerns long-term strategic planning. Individual countries increasingly rely on ‘grand strategy’ documents and long-term defence programmes that define national priorities and spending trajectories. These frameworks can provide stability and encourage political consensus across party lines. This means that legislatures need to scrutinise both such long-term strategic documents and more day-to-day policymaking. Continuous oversight ensures that governments remain accountable not only for broad objectives but also for the implementation of those objectives.

Institutional design remains critical for successful oversight. Strong committee systems, investigative powers, transparency requirements, and regular parliamentary debates all contribute to legislative influence. Furthermore, parliaments should invest resources in interparliamentary cooperation to exchange information and learn ‘best practices’, especially in the context of the European Union and NATO. As security challenges increasingly transcend national borders, interparliamentary cooperation can strengthen democratic accountability at multiple levels of governance.

In conclusion, parliamentary control of security and defence policy is an essential component of democratic governance. Although executives enjoy significant advantages in terms of information, resources, and agenda-setting power, legislatures perform a vital accountability function by scrutinising military deployments, intelligence activities, strategic planning, and defence procurement. The challenges are considerable, particularly in an era marked by geopolitical instability, the growing importance of intelligence, and pressures for rapid decision-making. Nevertheless, robust parliamentary institutions, transparent procedures, and active political debate can help ensure that security policy remains subject to democratic control. The process of parliamentarisation is therefore not merely a constitutional issue but a broader effort to reconcile effective security governance with the principles of democratic accountability.

Disclaimer: Views expressed are of the author(s) and do not necessarily reflect the views of The Statecraft Institute.