Both, probably. Any internal (or external) wobbling is easily remedied by another spectacular act of murderousness and inhumanity which reaffirms their power and impunity as well as clarifies the relative power relations of all the actors.
Anyone within our borders or without have any doubts about the state of play? Well, we'll just kill some people in a way that's maximally egregious and offensive to legal and social norms. Then for Act Two, we will face no consequences while making it crystal clear to everyone why we are facing no consequences. Thus is confidence restored. At least until the rush wears off and doubt, fear and paranoia begin to creep back in.
On balance though, seems to be working quite well for them so far.