From the NYT political blog:
Some of Mrs. Clinton’s rivals, including the campaign of Senator Barack Obama, went through the list of the Clinton’s financial holdings that Mrs. Clinton filed with the Senate and released a very detailed and critical analysis about where the Clintons had gotten and invested their money.
Mr. Obama’s aides circulated the memorandum to news organizations on the condition that news organizations not say where they obtained the information.
This turned into a bit of a dust-up because by all appearances, the Obama campaign got a little sloppy in circulating what turned out to be two critical memos. They ended up in the hands of the Clinton campaign.
Why would the Clinton campaign want to circulate documents attacking its candidate? Mrs. Clinton’s aides declined comment. But the Clintons have been seeking to undercut the effort by Mr. Obama to present himself as the face of a new-kind-of-politics that eschews these kind of attacks. [The Backstory on Obama-Clinton Attack Memos. The Caucus. June 15 2007]
Clinton seems to be winning at the moment.
The Obama campaign was forced to acknowledge authorship when the Clinton campaign got a copy and shared it with The New York Times.
For the Clinton campaign, drawing attention to a document attacking its own candidate had the effect of demonstrating that Mr. Obama, like other candidates, is not above a bit of political street fighting and, by implication, should not be allowed to cast himself as a champion of a purer version of public service. But in this case, the disclosure also threatened to create a substantive problem for Mr. Obama by leading an Indian-American group to accuse Mr. Obama of engaging in racial stereotyping. [A New Kind of Politics Closely Resembles the Old. NYT. June 16 2007]
Read also 2008: Not-So-New Politics, New Fallout.