Go read some news stories in old newspapers and you will see a much greater effort at objectivity. But be sure to look back before the onset of "opinion journalism" as it is called in the field or "advocacy journalism" before journalists thought they could change the world rather than just report on it.
They are sometimes still objective today, proving that they can be objective when they want to.
CNN is one of the best on the left. Here is a good example of journalism from their website:
http://www.cnn.com/2009/WORLD/asiapcf/12/10/pakistan.student.arrest/index.html
You will note that the reporters never gave any of their own opinions and only quoted others. If they are able to write a story like that and keep it objective then why can't they cover presidential elections, global warming, and health care in objective ways?
For the other kind of story you can go to
http://newsbusters.org/
to read example after example (just bear in mind that they cover all media and not just news)