CAIRO – President Mohammed Morsi is unlikely to worry if Egypt's Islamist-leaning draft constitution passes by only a small margin in a Dec. 15 referendum, since he and his backers tout his 51 percent election victory in June as a "popular mandate" that is beyond any challenge.

Still, an idea taking root among many secular Egyptians is that a constitution requires a reasonable degree of consensus to qualify as a charter for all – and that it is fundamentally illegitimate to ram one through by a simple majority despite opposition from key sectors of society that oppose giving religion such a major role in the affairs of state.

"It is irrational to have a constitution that does not genuinely represent everyone," said Kahlil al-Anani, a British-based expert on Egypt. "It is important that a constitution is passed with a comfortable majority, but it does not make the document less credible if it is a modest majority."