The evolution, it appears, is now complete. Barack Obama – who once supported same-sex marriages (when he ran for state senator in Illinois in 1996), then opposed them (when he ran for Senate in 2004 against Alan Keyes), and then was unsure what he thought (as president) – told ABC’s Robin Roberts, “I’ve 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.” The president added that this is a personal position and he still supports the concept of states deciding the issue on their own.

I have several thoughts on this development, beginning with the wisdom of the timing. The president announced his position one day after voters in North Carolina voted to support adding an amendment on marriage to its constitution, banning same-sex marriage. As a friend pointed out to me, the president was shrewd to wait until after yesterday’s vote, which allows him to look like he is willing to buck public opinion rather than looking like his endorsement carried no weight in the vote.

Then there is Obama’s explanation for his decision, which was both intelligent and familiar to those who have followed this debate. But there was also, as there almost always is with Obama, an element of moral preening.

“This is something that, you know, we have talked about over the years and [Michelle], you know, she feels the same way, she feels the same way that I do,” Obama said.

And that is that, in the end the values that I care most deeply about and she cares most deeply about is how we treat other people and, you know, I, you know, we are both practicing Christians and obviously this position may be considered to put us at odds with the views of others but, you know, when we think about our faith, the thing at root that we think about is, not only Christ sacrificing himself on our behalf, but it’s also the Golden Rule, you know, treat others the way you would want to be treated. And I think that’s what we try to impart to our kids and that’s what motivates me as president and I figure the most consistent I can be in being true to those precepts, the better I’ll be as a as a dad and a husband and hopefully the better I’ll be as president.

Set aside for the moment the theological dimensions of this issue, which are far more complicated than Obama portrays. What the president has done is not simply shift his position; it’s that he justifies his shift as something Jesus would support. The argument being deployed goes something like this: Michelle and I are practicing Christians. What we care most deeply about is how we treat other people. We believe in the Golden Rule. And if you do, you’ll support same-sex marriage. If you don’t, you’ll oppose it.

Is it uncouth to point out that in 2004, when it was politically convenient for him, Obama argued that his religious faith dictated that marriage should be between a man and a woman? Now his faith dictates the opposite. What has changed during the last eight years isn’t the Golden Rule or the words and teachings of Jesus, the New Testament, or the Hebrew Bible; it is what is most politically expedient for a certain politician from Chicago.

Barack Obama wouldn’t be the first politician to shape his views based on the prevailing political winds and the needs of the moment. There are certainly serious arguments to be made on behalf of same-sex marriage, just as there are serious arguments to be made against it. But what I hope we’ll be spared from is Obama, having gone back and forth and back again on gay marriage, lecturing us about how his latest stance is the only principled and morally justifiable one.