Harriet Miers was an interesting matter. Miers was top of her class at a decent regional law school (SMU IIRC) and the first woman partner at some big big Texas firm. for years, liberals and some populist conservatives have been complaining that ever since Stevens (NWU), every supreme court justice has come from a very small group of elite law schools-Harvard (Breyer, Souter, Scalia, Roberts, Kennedy and Ginsberg {who transferred to Columbia due to her husband's hospitalization in NYC) and Kagan) Yale (Thomas, Sotomayor, Alito) and Stanford (SDO and Rehnquist). Many have suggested that the Court needs the perspective of a justice who didn't go to one of those three schools which are generally ranked as three of the top five nationally (U of Chicago is almost always in that group-while Michigan, Columbia, Penn, Duke, Cornell, NYU, UVa, and G'town rotate into that group depending on the year and the raters)
So HM was seen as a loyal GOP pick who went to some school other than H, Y, or Stanford but who had top grades and had done well professionally
UNDER the current standards (law review at Harvard, Yale or Stanford) she was not "qualified" but her credentials were better than many who had been on the court in years past. the CJ Warren Burger was a political hack for example who went to a much weaker law school. it has only been the last 30 years or so that nominees for justices have come only from these top schools