NATO's Article 5 states that an attack against one member is considered an attack against all members.
November 19, 2025
high
security_policy
Foundational collective-defense principle of the North Atlantic Treaty Organization.
The Schengen Area is a passport-free travel zone comprising 25 EU member countries plus Liechtenstein, Iceland, Norway, and Switzerland.
November 19, 2025
high
institutional
Schengen facilitates cross-border movement without routine ID checks among participating states.
The European Union is a political and economic bloc composed of 27 member countries.
November 19, 2025
high
institutional
The EU is a multilateral organization for economic and political integration among its member states.
Some European railway networks use mismatched track gauges across countries, which complicates transporting heavy military equipment such as armored vehicles between western and eastern Europe.
November 19, 2025
high
infrastructure
Differing railway gauges and interoperability issues hinder cross-border movement of heavy military logistics.