Bush the Elder immediately comes to mind. President W. is much more politically adept than his father, however, and is smarter than he likes to let on. I have no problem with him being friendly with Ted Kennedy. Asking the President to do otherwise is silly.
However, I think most conservatives would have a major problem with any bill that Ted Kennedy supports. Kennedy would never, ever, under any circumstances, support legislation that would actually reform the public school system. The teacher's unions, and his own leftist ideology, would absolutely prohibit it.