Obama flips again

First he did it on FISA and then on his promise to stick with the public financing of his campaign. In his most recent reversal, Obama abandons Federalism. Obama previously said he opposed same-sex marriage, but that must not have polled well because now he writes, in a letter to the BLBT Democratic Club he says he supports extending "fully equal rights and benefits to same-sex couples under both state and federal law." Ed Morrissy on the subject:

There are only three possibilities for why Barack Obama has had to change his mind on almost every policy he has mentioned in this campaign:

1. He’s a liar who says what each audience wants to hear.
2. The election debate has changed his perspective on every issue.
3. He has no clue on any of the issues.
Only the second reflects any positive quality, that of open-mindedness, but it also carries with it the underlying unreadiness of a man who has only three years of national political experience for the Presidency. Assuming the best of intentions, Obama has no firm stands on any principle or policy.

So, which do you think it is? I'm leaning toward #1, but not ruling out #3.