After the UN General Assembly voted to raise the Palestinian Authority's status from an observer entity to a non-member observer state, Susan Rice delivered a particularly strong pro-Israel statement in opposition to the resolution.
Yes, Rice has voted against anti-Israel resolutions before but has done so with very little enthusiasm as was the case when she voted against a UN Security Council Resolution condemning Israeli settlements in February 2011. Despite her opposition to the resolution, she spent most of her speech calling Israeli settlements illegitimate.
So why has Rice changed her tune? Well, of course, to mollify opposition to her becoming the next Secretary of State should President Obama choose to appoint her. I'm not sure a single forceful pro-Israeli statement will be enough to overcome her statements on Benghazi but it could certainly help her with Senators who are sitting on the fence.