A golden rule for rules on outside-counsel diversity

Amidst all the publicity about diversity (See my posts of Sept. 4, 2005 about definitions; and Dec. 4, 2005 on minorities.), why don’t law departments take the following powerful position regarding diversity among the lawyers its outside counsel assign to its matters?

“Your law firm must use on our matters diverse lawyers in proportion to our department’s diversity percentages.” That insistence on a close approximation (or better) pushes the law department to define who is diverse, hire and retain a diverse group of lawyers, and exemplify the principles it demands of its external lawyers (See my post of March 17, 2006 about in-house hypocrisy.).