In 2024, Poland's defense spending as a share of gross domestic product was **** percent, the highest of all NATO member states, followed by Estonia at **** percent, and then the United States at **** percent. It is a target of NATO that every member country should spend at least two percent of their GDP on defense. As of this year, it is estimated that all but eight of the alliance's 31 member states were meeting this target. The average expenditure on defense expenditure across all NATO member states was **** percent in 2024, compared with **** percent in the previous year. NATO, Trump, and the War in Ukraine Russia's full-scale invasion of Ukraine in February 2022 shook many European powers out of a creeping complacency that had set in since the end of the Cold War. It led directly to the applications of Sweden and Finland to the alliance in 2022, with the latter joining later that year. The conflict has however also underlined how Europe's security is still underpinned by American military power, with the United States the main contributor of military aid to Ukraine. Furthermore, in overall defense spending, the U.S. spends far more than the rest of NATO combined. The current Trump administration has frequently criticized NATO states that they see as taking advantage of this discrepancy, urging other members to reach and even exceed the two percent threshold. Article 5 triggered in the aftermath of 9/11 While NATO was founded with the aim of deterring the Soviet Union in the Cold War, its central defense clause "Article 5" whereby an attack on one member is considered an attack on all, has only been triggered once; after the 9/11 terrorist attacks on the United States. NATO's involvement in the subsequent War in Afghanistan was a direct result of this, with troops supporting the operation from across the alliance. Although NATO's focus drifted towards counter-insurgency, and the threat from terrorism in this period, its original purpose has become far more important recently.

U.S. military spending/defense budget for 2022 was 876.94 billion US dollars, a 8.77% increase from 2021.

<ul style='margin-top:20px;'>

<li>U.S. military spending/defense budget for 2021 was <strong>806.23 billion US dollars</strong>, a <strong>3.58% increase</strong> from 2020.</li>
<li>U.S. military spending/defense budget for 2020 was <strong>778.40 billion US dollars</strong>, a <strong>6% increase</strong> from 2019.</li>
<li>U.S. military spending/defense budget for 2019 was <strong>734.34 billion US dollars</strong>, a <strong>7.6% increase</strong> from 2018.</li>
</ul>Military expenditures data from SIPRI are derived from the NATO definition, which includes all current and capital expenditures on the armed forces, including peacekeeping forces; defense ministries and other government agencies engaged in defense projects; paramilitary forces, if these are judged to be trained and equipped for military operations; and military space activities. Such expenditures include military and civil personnel, including retirement pensions of military personnel and social services for personnel; operation and maintenance; procurement; military research and development; and military aid (in the military expenditures of the donor country).

In 2022/23, the United Kingdom's defence spending as a share of Gross Domestic Product is estimated to be 2.2 percent. During this time period, the UK's defence spending was at its highest in 1955/56 when 7.6 percent of the UK's GDP was spent on the military. Defence spending has fallen considerably throughout this period, especially after 1984/85, and then at a much faster pace after the end of the Cold War in 1991. It is estimated that defence spending as a share of GDP fell to its lowest level between 2016/17 and 2018/19 when it was just 1.8 percent. Armed forces fall to record lows in 2024 Since the early 1950s, there has been a consistent reduction in the size of the UK's armed forces. The importance of Britain maintaining a large standing army declined following the collapse of the British Empire by the late 1970s, and the end of the Cold War around a decade later. At the start of the 1990s, there were approximately 300,000 personnel in the armed forces, with this falling to 200,000 by 2005. Following a further strategic review of the army's capabilities in 2010, additional cuts to personnel were implemented, with cuts of approximately 50,000 throughout the 2010s. As of 2024, there were 75,320 personnel in the Army, 30,800 in the Royal Air Force, and 32,000 in the Royal Navy and Marines, a total of 138,120 active personnel. The UK and NATO The UK is one of the twelve founding members of the North Atlantic Treaty Organization (NATO), a military alliance formed in 1949. NATO's initial purpose was to defend Western Europe against the Soviet Union, with its role evolving to include peacekeeping and counter-terrorism after the end of the Cold War. As of 2025, the alliance includes 32 nations, with just two of these (Canada and the United States) outside of Europe. The United States is by far the largest military power in the alliance, dominating in terms of manpower, equipment, and military spending. Donald Trump's return to the White House in 2025, who has been skeptical of NATO, may prove difficult for the alliance should he distance the U.S. from Europe's security challenges.

In 2024, there were approximately 121,900 men in the armed forces of the United Kingdom, and 16,220 women. The reduction in personnel witnessed by the British Armed Forces in recent years is the result of a conscious attempt by the UK government to cut costs and modernize the military. This policy has been pursued since the 2010 Strategic Defence and Security Review, which among other things sought to replace many full-time regulars with reservists, and to end the UK’s permanent deployment in Germany. Cuts across air land and sea While the army has born the brunt of these cuts to personnel, all branches of the armed forces have also had to contend with the same issue. Since 2012, the Army has seen its personnel reduced by around 28,800, the RAF by 9,200, and the Navy by around 3,540 While the share of GDP spent on defense has not fallen quite as dramatically since 2012, over the long term, the UK has almost halved defense spending since the end of the Cold War. As of 2021, the UK spent 2.3 percent of GDP on defense, slightly above the minimum NATO requirement of two percent of GDP. Recent geopolitical events, such as the Russian invasion of Ukraine, have led to renewed calls for increased defence spending, with the current UK government aiming to spend 2.5 percent of GDP in the near future. Age of personnel In 2024, the average age across all ranks and branches in the UK armed forces was 31. This was the average age for all branches of the armed forces, except for the RAF, which had an average age of 33. During the same year, there were approximately 54,800 people in their 20s in the armed forces, compared with 45,410 in their 30s. Additionally, there were only around 7,760 people under the age of 20 in the armed forces, and just 90 aged 60 or over.