“Forced” is too strong of a word IMO. I think Putin was wrong to invade, but US had pushed him into a corner and kept on pushing. Many experts like John Mearsheimer had predicted for years that if NATO kept pushing up to Russia’s borders, and the US kept overthrowing Russia -friendly regimes like in Georgia and Ukraine, war would result. Putin and other Russian leaders explicitly warned us repeatedly that Ukraine could not join NATO, or be used as a site of nuclear weapons. They demanded Ukrainian armed forces and neo-Nazi militias stop shelling ethnic Russians in the Donbas region. Biden and company basically laughed them off and said they would do what they wanted to do. So, not “forced” but “provoked” is the word I would use.