The Boundaries of Ukraine's Right to Self-Defense

There is a debate in Germany about whether Ukraine has the right to strike back across the border as Russia continues its attacks on civilian targets. Under international law, Ukraine has the right to self-defense, including military strikes on Russian territory, as long as they target military objectives. However, attacks on civilian populations are not permitted. The use of applicable weapons, such as drones, missiles, and aircraft, is allowed, but Ukraine has made political agreements not to use Western-made weapons to strike Russia's hinterland. The red line for other governments varies, with some willing to deliver long-range cruise missiles to Ukraine. The moment when a third country becomes a party to war is not entirely clear in international law, but supplying weapons and munitions to Ukraine is not considered active participation. The Kremlin considers NATO countries supplying weapons to Ukraine as belligerents, and there are concerns that Russia may escalate the war and attack countries supporting Ukraine. The European Union emphasizes Ukraine's right to self-defense and urges Russia not to use the recent drone attacks as a pretext for further escalation.