Admissions is an arcane process, especially in the top schools. Logically, if George W. Bush has attended and graduated both Yale AND Harvard, then it is indisputable that there are ways for someone with an intellect that doesn't quite rise to the level of middling to get into those schools. How exactly that can happen is not entirely clear, but legacy (particularly if the legatee's parents have been generous to their alma mater), affirmative action and celebrity have a lot to do with it.
And even more cynically, I have a suspicion that top schools will admit, under one pretext or another, a few applicants who are clearly less qualified than most, just so they can plausibly claim (as they do) that there is no LSAT and GPA cutoff, and that everyone who is interested in attending should apply. Schools obviously like to boast about having a huge pool of applicants, and they also like those $70 checks that come with the applications. If Harvard has 5,000 applicants annually, that amounts to some $350,000. That would go a long way in paying for the salaries of the admissions officers.
I myself will soon be testing the power of affirmative action, I have a 3.43 GPA from a crappy state school and an LSAT of 171 with no notable extracurricular activities. Normally, I don't think those credentials would be enough for me to be considered at Hahvahd, but by checking "Hispanic or Latino" in the app, who knows? It could just be my trump card.