we begin tonight with new details about president obama s personal evolution on a potent political issue, same-sex marriage. i have just concluded that for me, personally, it is important for me to go ahead and affirm that i think same-sex couples should be able to get married. with that in that oval office vint with abc news, the president officially switched his position. in 2008, he ran as i acandidate who opposed same-sex marriage. cnn is told he is ready to support it and green light those that want to add language to the 2012 campaign platform. why the switch? i had hesitated on gay marriage in part because i thought civil unions would be sufficient. that that was something that would give people hospital visitation rights and other elements that we take for granted. and, i was sensitive to the fact that for a lot of people, the word marriage was something that o evokes very powerful traditions and religious beliefs. over the course of several years, as i talked