As the WEU's functions were transferred to the European Union 's (EU) European Security and Defence Policy (ESDP) at the turn of the 21st century, the Western Union is a precursor of both NATO and the military arm of the EU.
As the WEU's functions were transferred to the European Union 's (EU) European Security and Defence Policy (ESDP) at the turn of the 21st century, the Western Union is a precursor of both NATO and the military arm of the EU.