Is Bush an appropriate commencement speaker for Notre Dame?

I do not envy the administrators who have to choose commencement speakers at Catholic colleges and universities, and I do not have any bright-line rules in mind for navigating these issues, so please take these questions as sincere and snark-free:  Given George W. Bush's record on the death penalty as Governor of Texas, should Notre Dame have invited him to be the commencement speaker in 2001?  And now given what we know about his record on torture as President, should Notre Dame invite him to be commencement speaker in 2009?  If Bush is fine, but Obama is not, how exactly do you articulate the difference in terms of appearing to support those who "act in defiance of our fundamental moral principles?"  Abortion stands alone as a disqualifier?  Some other explanation?