It wouldn't excuse Libby's alleged lying...if he did lie, then it's wrong, plain and simple...However, if his "lie" is based on the reporter's saying they didn't know about plame until they heard it from Libby, and it is discoverd that this info was common knowledge (as it most certanly seems to have been), then there are more folks that should be on the hot seat than just Libby (and they're all in the dnc/msm).
This whole thing stinks to high heaven of a CIA/DNC/MSM generated plot to try and get the rats back in power by taking down this Administration by any means possible. [\tin foil hat]
The alleged lie is not based on that.
http://www.usdoj.gov/usao/iln/osc/documents/libby_indictment_28102005.pdf