Why? And really, how credible is the ABA? They should be extremely credible, but I seem to remember that Pres. Bush said while he would listen to their input, it would not necessarily be the only input relied on.
Just take a look at this list for a moment. http://www.abanet.org/scfedjud/ratings108.pdf
and the following letter from the ABA to Sen. Specter.
http://www.abanet.org/scfedjud/ratings108.pdf
The letter gives a good explanation of the peer review process.
More than a few conservatives....including Miguel Estrada and Priscilla Owen received a "well qualified" rating.
And, the ABA is quite credible. Political views are not considered by these ratings.