If the motive was to give ex-Clinton oficials a little better "spin" before the 9-11 Commission, I don't think this story will go very far; such a motive would only be played up by the press if the Bush administration did it. Then it would be big news. But if Berger were found to be acting on behalf of the Kerry campaign, I think it might be a different story. Then the press might go after it.
If Kerry is/was on the national security committee, and, these documents show that the Clinton Admin AND Kerry had advance warning of the attacks and did nothing... then BOTH Kerry and Clinton go down in flames.
FR attention required: Clinton's consigliere, Lindsey, was contacted after Berger doc theft
Maybe it helps Kerry indirectly, because it is designed to damage Bush and therby it benefits whoever the Dem turned out to be.