This absolutely nothing at all like Libya, where an ongoing civil war resulted in UN resolutions of force.
Snatching a national leader of a country with which the US is not at war, has had zero force authorization, off of that leader's own soil, is completely unprecedented, no matter how bad that leader is.
Not sure if it's really unprecedented, but I think all wars should be like that. Go kidnap or kill the leader but please leave everyone else alone. Also by all means go and capture the US' leader if you think you need to retaliate.