This is an interesting question, even if I write so myself. The case for your consideration:
The New York Times, The Washington Post and Fox News have made exclusive agreements with a conservative author for early access to his opposition research on Hillary Clinton, a move that has confounded members of the Clinton campaign and some reporters, the On Media blog has confirmed.
"Clinton Cash: The Untold Story of How and Why Foreign Governments and Businesses Helped Make Bill and Hillary Rich" will debut on May 5. But the Times, the Post and Fox have already made arrangements with author Peter Schweizer to pursue some of the material included in his book, which seeks to draw connections between Clinton Foundation donations and speaking fees and Hillary Clinton's actions as secretary of state. Schweizer is the president of the Government Accountability Institute, a conservative research group, and previously served as an adviser to Republican vice presidential nominee Sarah Palin.
I see three potentially serious problems with these exclusive arrangements.
First, depending on what newspapers are supposed to have as their objective*, getting opposition research on only one candidate can bias the reporting in the papers. If conservative muckrakers are more diligent than liberal ones, the American people (how I love to be able to write that!) will be mislead, assuming that the Republican candidates might also have all sorts of skeletons in their mahogany cupboards.
Second, assuming that those at the newspapers know how to judge the research of Schweizer's book may be a form of hubris. Or at least we should not just be told that there will be experts looking at all the stuff.
Third, and this links to my second point, using a book BEFORE it is published means that the newspapers won't have access to the expert criticisms which follow the publication of a book. It's as if the book is allowed to hold the stage all alone, when the correct approach would be to wait to see what experts in the field might have to say about it.
*The naive me thinks that the newspapers should try to be objective, search for as much truth as people can agree on and provide voters with factual information that will help their votes. Psst, Maureen Dowd, writing about Hillary Clinton with all sorts of sexist terms isn't helpful for voters.
But other objectives are possible. For instance, to make the most money possible out of gullible readers.