In this clip Stewart claims that a real debate about Israel is only acceptable in Israel. Based on my experience in the US and in Israel I would say his comments are fairly accurate.
With regard to Obama's pandering at the annual policy conference of the American Israel Public Affairs Committee (AIPAC), he did at least offer some suggestions to Israel.
“Israel can,” he said, “ease the freedom of movement for Palestinians, improve economic conditions in the West Bank, and to refrain from building new settlements — as it agreed to with the [President George W.] Bush administration at Annapolis.” Inter Press Service
If Obama is elected, I hope that he will be able to critique the harsh violence of both the Palestinians and the Israelis.