Well what it has become is probably due to what happen in the Summer of Mercy protests in 1991, but I don't think the evangelicals and the issue of abortion was nearly as hand and hand until then. Yeah many were silently opposed to it, but Fox really started rallying them against it in the 90's, and its become the face palm topic ever since.
But I do believe that Graham's original goal in getting Christianity in politics was more anti communist than to seize power, but doing so probably had more lasting negative effects on society than positive. It pretty much branched off as white supremist trying to rewrite the constitution because they interpret the Bible a certain way. I think Graham saw what he created and started to walk back his involvement in politics because of it.