Even though there is no central authority that speaks for Islam, there are times and places when an authoritative Doctor of Religious Sciences (of Islam) speaks for Islam; i.e. his legal opinion becomes the de facto position of Muslims everywhere.
Ayatollah Khamenei’s statement of 12/28/2008 is one such case. You can find the text @ http://english.khamenei.ir//index.php?option=com_content&task=view&id=1022&Itemid=16. His statement characterizes the Israel-Hamas War as the analogue of the wars of the Prophet against the idol-worshippers of Mecca. With a few words, Mr. Khamenei has shaped the Muslim view of the Israel-Hamas War for years, if not decades, to come.
No Muslim political leader can challenge his statement , for doing so now will be tantamount to going against Islam. No religious leader – Shia or Sunni – will dispute his statement.
Here is Prince Turki al-Faisal of Saudi Arabia (a moderate according to the common US-EU usage of that term) in a speech at the opening of the 6-th (Persian) Gulf Forum on January 6th, “The Bush administration has left you (with) a disgusting legacy and a reckless position towards the massacres and bloodshed of innocents in Gaza…Enough is enough, today we are all Palestinians and we seek martyrdom for God and for Palestine, following those who died in Gaza.”
In my opinion, Israel has now blundered into an implicit war with Islam. Mr. Khamenei’s statement has closed the door to any peace plan along the lines of Oslo, Taba, the Quartet, Tony Blair, etc. All that is now even theoretically possible is a Hudna – a long cease-fire. A separate Syria-Israel peace track is no longer possible since the Alawite Elders will not go against the rest of Islam by having Syria conclude a separate peace treaty with Israel.
Which brings me to my final opinion: even a Hudna will presently require the formation of a Concert of Middle East or some such.