[JURIST] Iraqis prepared to go the polls Saturday to cast ballots in a critical referendum [IECI factsheet, PDF] on a draft constitution [JURIST news archive] the terms of which were only finalized earlier this week [JURIST report] at the end of a high-pressure, high-stakes negotiating process urged on by the United States, too late to be reflected in millions of print copies distributed around the country by the UN [JURIST report]. Some 15.5 million Iraqis - Shiites, Kurds and Sunnis - are eligible to vote at some 6100 heavily-guarded polling places. A simple majority of voters [IECI voter information pamphlet, PDF] will suffice to approve the federalist charter, but a two-thirds majority against it in three or more of Iraq's 18 provinces will force its defeat. Supporters hope that last-minute changes to key terms [JURIST document] will entice reticent Sunnis to support the text, but despite its late endorsement by a leading Sunni party [JURIST report] key Sunni leaders who have campaigned against it on national unity grounds and who say the wording changes do not assuage their concerns still predict it will fail [JURIST report]. Rejection of the charter would precipitate a major political crisis in Iraq, but even ratification will not guarantee stability, as the document is pointedly open-ended and subject to further change in possible future referenda. The full vote count is expected to take up to five days. Reuters has more; the New York Times provides additional coverage. From Baghdad, the Iraq the Model weblog offers an Iraqi perspective on the imminent vote.