Wasteland 3

You can also get this by choosing the dialogue option when talking to Valor "Why shouldn't I arrest you?" or something like that. After this you will have to clear out everyone in the white house, as well as fight the Reagan statue outside and enemies before returning to Valor in the server room where you can call for him to be extracted. If you are doing it this way, it is best to avoid the mission that upgrades Reagan as this will make him harder to fight when he is upgraded. Also, before reaching Valor to have him extracted make a save, after the achievement reload and have someone with a shotgun attack him to start combat as you can't just select him with an attack I'm guessing a grenade would work as well and then just kill him to get the achievement for killing him.

If you are going to attack the Gippers head on like that, you might also want to use the 3 terminals around the compound to sabotage the Reagan statue so it self destructs. That way you won't have to worry about fighting it and should make your life easier. The Gippers won't know it was you that sabotaged the statue, so you should be safe to do so as long as you meet the required skill checks.