It's kind of surprising that the change is that low when an American President is basically waging a diplomatic offensive against Israel. Good news in the long run.
In 2009, he unilaterally changed the US' definition Israel's borders, declared Jewish homes in Jewish areas of Jerusalem to be "settlements", and then spent weeks publicly denouncing Israel. It took his own party telling him to stop demonizing a US ally to get him to stop, and he's held a grudge ever since.
To be truthful, it's because Democrats were blackmiled by AIPAC, not because they were an ally.
