At a newspaper I worked at near philly, the newsroom was in favor of Clinton over "any Republican" by a tally of 19 to 4. How did I know??
I took a survey of all the news reporters in the newsroom in 1995 after I was told by colleagues that taxcuts were racist and that I had to be more diverse in the people I quoted in my stories.
The paper I work at now, although the editorial page leans to the right, is about the same percentage of liberals in the newsroom. (12 libs to two conservatives)
My theory is that people who think they know it all and want to change the world (in other words, Libs) are more prone to becoming "journalists".
As for myself, I just fell into it by chance, and don't even have a college degree in journalism.
I was always a decent writer in high school, and have good contacts with people in the community.
What amazes me is that news rooms who tout the benefits of diversity don't seem to include political diversity.