Original sentence: Liberal bias in the media occurs when liberal ideas have undue influence on the coverage or selection of news stories
Edited sentence: Liberal bias in the media occurs when liberal ideas have undue influence on the coverage or selection of news stories due to the overwhelming preponderance of liberal reporters and editors in most major news organizations.The bias becomes evident in the non-neutral treatment of controversial issues such as gay rights, abortion, the place of religion in society, and most recently with the media's overwhelmingly positive coverage of Barack Obama compared with George W