Hard to say. Every president other then Obama also recognized Jerusalem as the capitol of Israel. Bill Clinton certainly did. But the reason is that it means America believes that Israel has a right to exist, and a lot of liberals basically think that Israeli do not deserve to live in the country that they built. You see Israeli built Israel, but were chased out of it. After WW2, with the help of England, they offered Palestinians a lot of money if they could have that space of land back, and Palestinians accepted that money. But later, they decided they did n't care that they took the money, they wanted to have the land back. By then many Israeli had already resettled, and they had a war, Israel won. Thats how it is. Because Israelis built Israel, usually America supports them, but Obama has very strong ties to Islam, and Palestinians are Muslim, so he sided with them, and so do liberals.