Agenda setting is the idea the media have a powerful influence over the issues that people think about because the agenda is already set by journalists. This is because people can only discuss and form views about the issues they’ve been informed about.
The power journalists and others working in newsrooms have in society is clearly extensive. By having the ability to set the agenda, journalists decide the main topics of discussion for people in society. This can mean the public never discuss some subjects because they are not aware they’re on the agenda for discussion. Bachrach and Baratz termed the prevention of issues getting on to the agenda as non-decision making (what Stephen Lukes termed the 2nd face of power).