Even before starting work as chairman of a U.N. human rights commission investigating the Gaza war, Canadian law professor William Schabas has been vilified as an apologist for Iran who is incapable of setting aside his perceived anti-Israel bias.

Full-page adverts have been taken out against him in The New York Times, Wall Street Journal and Washington Post, while the Facebook page of Rabbi Shmuley Boteach, a leader of the anti-Schabas campaign, has attracted more than 30,000 "likes."

The makeup of Schabas's commission is still being finalized — George Clooney's fiancee Amal Alamuddin turned down the invitation so another one or possibly two members must be found — but already he is worried about whether the team will be allowed to get into the region to conduct its inquiry.