If Putin was not in charge, getting old, and wanting to leave a legacy, would Russia have invaded Ukraine?
One of the main reasons the China - Taiwan situation is heating up is that Xi wants to cement his legacy alongside Mao and he is also getting very old.
The USA invaded Iraq for no other reason that Bush wanted to finish what his daddy had started. They had nothing to do with 9/11.
The UK launched the defence of the Falkland Islands because Maggie Thatcher wanted it. There was zero economic or military benefit in doing so.