Clark: The problem with the 10-percent rule in Texas is that it grants students automatic admission to the UT system even if they aren’t ready for it. I doubt seriously that 10 percent of the graduates at the very worst high school in Texas can handle the rigors; letting them in anyway is an enormous disservice to these supposed beneficiaries, who will struggle and flunk out at much higher rates than they would at lesser universities or community colleges. Perhaps this is preferable to a regime of racial preferences. But it is far from ideal, and we shouldn’t hesitate to say so.