I don't see an issue with a Christian supporting Romney for President (after all, I'm now supporting Mitt), but Liberty's invitation crosses the line because, after all, it is a Christian univertiy and not a Mormon one. I wouldn't nor will we ever expect a Mormon university such as BYU to invite an Evangelical Christian to deliver a commencement address. Voddie Baucham's remarks, although direct and may appear harsh, are Biblically solid:
There is a bit of a "revolt" going on at Liberty University right now over the decision to have Mitt Romney as this year's Commencement Speaker. Ironically, Romney will not be the first Mormon to give a commencement address at the Fundamentalist Christian (Religions Right/Neo Conservative/Republican) University. Glenn Beck gave the commencement address two years ago!
I've often said American Christians are far more "American" than they are "Christian". The problem is even worse at America's "Christian" Universities. Remember, folks, Mormonism is a Cult! More importantly, they make a mockery of Christ (viewing him as the spirit brother of Lucifer who once was a mere man as we are), and of the Father (whom they view as having had sex with Mary). [Emphasis in bold is mine].