AP Photo/Michael Sohn
- The US and NATO pledged to protect "every inch of NATO territory" amid Russia's assault on Ukraine.
- Ukraine has expressed interest in joining the alliance but has never been formally admitted.
- Some of the country's neighbors are long-standing members of the North Atlantic Treaty Organization.
When Russia invaded Ukraine a year ago last February, the National Atlantic Treaty Organization swiftly condemned the unprovoked assault as a war of aggression against Ukraine, a sovereign and peaceful country.