See also Agenda Denial
So, getting something onto the political/policy agenda takes a mixture of resources (money for adverts, personal connections), timing, luck (being able to ‘exploit’ a crisis/tragedy/accident).
Just because something is a problem does not mean it is automatically an issue (see Blumer, 1971).
The Multiple Streams Approach was developed to explain this agenda-setting phase, which is sometimes seen as distinct from decision-making, policy formulation/implementation/evaluation (though of course they iterate, overlap etc)
Advocacy Coalitions Framework
Wolfe, M., Jones,B.D. & Baumgartner, F.R. (2013).A failure to communicate:Agenda setting in media and policy studies. Political Communication 30(2): 175–192.