The CSDP is implemented using civilian and military contributions from member states' armed forces, which also are obliged to collective self-defence based on Treaty on European Union (TEU).
Five EU states host nuclear weapons: France has its own nuclear programmes, while Belgium, Germany, Italy and the Netherlands host US nuclear weapons as part of NATO's nuclear sharing policy. Combined, the EU possesses 300 warheads, and hosts between 90 and 130 US warheads. Italy hosts 70-90 B61 nuclear bombs, while Germany, Belgium, and the Netherlands 10-20 each one. The EU has the third largest arsenal of nuclear weapons, after the United States and Russia.
The combined military expenditure of the member states amounted to €223.4 billion in 2018. This represents 1.4% of European Union GDP. European military expenditure includes spending on joint projects such as the Eurofighter Typhoon and joint procurement of equipment. The European Union's combined active military forces in 2016 totaled 1,410,626 personnel.