turning into a sewer
1. Where principled reporting typically relies on 'shoe leather', 'common sense' and a 'respect for the truth', what currently passes as journalism is regularly failing its audience in many crucial respects.
2. The coverage is distorted by celebrity and the wohship of celebrity; by the reduction of news to gossip, which is the lowest form of news; by sensationalism, which is always a turning away from a society's real condition; and by a political and social discourse that we -the press, the media, the politicians and the people - are turning into a sewer.
3. The journalistic field possesses a relative degree of autonomy from other fields of cultural production, such as the juridical, literary, artistic or scientific fields.
Shoe leather means walking around- ie, basic hard work going around collecting information.
A sewer is a place where human waste goes, so it is implying that the media and politicians are turning into something dirty and horrible.
The third suggests that journalists are detached from and independent of other areas of culture.