Short situation description in diplomatic terms:
- Qassem Soleimani was in Iraq on an official visit, by invitation from Iraq's government
- he was an official Iranian representative
- US confirmed official order for striking
So, what we have.
Some "state A" officially assassinates some official from "state B", during his diplomatic visit to "state C". Without any further UN sanctions/international blame/just any diplomatic consequences from the "international community" to "state A".
Does it mean that such actions are now in fact legal?
Does it confirm unipolar world slightly moving to the "rule of power"?
PS: Small edit, to make question more clear.
"Legal" here means "Legal according to internation laws". Because each and every state can create inner laws about asassinating some arbitrary list of persons - but iterating such a list would not (or am I mistaking and it would?) be legal according to international laws.