Morsi could be tainted by allegations of voting violations instigated by Islamists and reported by rights groups. The charges could cast doubt on the democratic credentials of the Islamists and lead to damaging analogies between Morsi's administration and Mubarak's authoritarian regime, which oversaw massive electoral fraud for years.
The opposition is demanding an investigation of alleged wrongdoing in the vote.
The Brotherhood insisted violations were limited and should not affect the referendum's integrity.
But prominent lawyer and rights activist Negad Borai described the violations as systematic.
"What happened in the referendum could lead to violence and bloodshed if repeated in a parliamentary election when the stakes are higher," he warned.
Hendawi is the Associated Press chief of bureau in Cairo.
An AP News Analysis