In its Nov. 29 editorial "Affirmative Geography," The Post acknowledges some policy drawbacks to guaranteeing state college slots to a set percentage of each high school's graduating class but didn't mention a bigger problem: Such guarantees are unconstitutional.

It is as illegal for a state to choose a selection device with an eye toward its racial and ethnic impact as it is to adopt overt quotas. Suppose colleges put more emphasis on the SAT in order to keep the number of blacks and Hispanics down. All would condemn such a move, and so it ought to be equally objectionable to use geography as a means of capping Asians and whites.

Nor is there any doubt that achieving a particular ethnic mix is the reason behind Florida's and Texas's adoption of a "20 percent plan" and a "10 percent plan," respectively. As The Post said, geography is being used as a "proxy" for race--and that's what's illegal.

The class-percentage approach also sweeps the problems under the rug. The reason that a disproportionate number of African Americans (and, to a lesser extent, Hispanics) are not the best qualified to go to college is shoddy public schools, peer pressure that labels studying hard as "acting white" and, too often, a lack of two-parent support at home (72 percent of children born out of wedlock are black vs. 21 percent for whites).

DAVID GERSTEN

Vice President

Center for Equal Opportunity

Washington