The Law of Unintended Consequences

 Putin's excuse was eastward expansion of NATO.  4/13/22 Washington Post:

BRUSSELS — Finland will launch an immediate debate on joining NATO, Finnish officials said on Wednesday, as the country reconsiders its longtime stance outside the Western military alliance following Russia’s invasion of Ukraine.

Prime Minister Sanna Marin said that a decision would be made in coming weeks.

“There are different perspectives to apply (for) NATO membership or not to apply and we have to analyze these very carefully,” she said at a news conference in Stockholm, according to Reuters. “But I think our process will be quite fast.”

Marin spoke alongside Swedish Prime Minister Magdalena Andersson, who said Sweden was also re-examining its position outside NATO, after Russian President Vladimir Putin’s Ukraine offensive plunged Europe into its most serious security crisis since World War II.

 

Invade a relatively weak nation and get your rear handed to you.  Invade NATO members and Russia either gets itself destroyed in nuclear holocaust or Finns occupy Moscow.  Smooth move Putin.