Obama is constantly making promises he can't keep. He can't force Israel to go back to pre-1967 borders. So stating it, is a position that is meaningless because it will never happen. Israel has to be able to defend itself and Netanyahu is correct when he said in his speech to Congress that borders will be negotiated not forced on the players.
source: http://nation.foxnews.com/president-obama/2011/05/24/op-ed-anti-israel-president