> This is not the norm for a definition of a combatant, and if we adopt the norm Iran has created, then we have to accept that in reality the US and EU have been at war with Russia, Iran, and North Korea since 2022 as the US and EU provide targeting intel and resupply munitions for Ukraine and Iran+NK provide lethal munitions and boots on the ground to Russia for their war in Ukraine.

There are no definitions, only established usage. It has been well established, most recently in the Ukraine war, that intelligence and material support do not mean direct involvement in a war. Assassinations, cyberattacks, and sabotage are also allowed to some extent.

Active involvement in combat operations is another story. You can't make your troops immune to counterattacks by placing them in a third country that is nominally neutral. If they are actively involved in the war, they are a legitimate target, as is the infrastructure supporting them.

There is no exact definition of what counts as active involvement. Not the least because wars tend to be situations, where everyone is acting in bad faith.