Whatever their decision - to convict, acquit or agree to disagree and return as a hung jury - they have a huge burden to carry and a vast amount of evidence to sift through.
Maintaining the routine they have followed since their sequestration began in January, the jury will be driven to the courthouse from their hotel every morning and return at night. Until they reach their verdict, they will deliberate six days a week in a small room.
The nine women and three men, nine of whom are black, two white and one Hispanic, hold the responsibility for Mr Simpson's fate, and the social unrest that could result from a guilty verdict.
Last week, as the two sides presented their closing arguments, analysts' predictions shifted between verdicts. Will jurors be seduced by the defence's plea to acquit? The kernel of the defence argument is that the police framed him and that the jury should now send a message about the racial divisions in Los Angeles and, by association, America. That is fraught with difficulties.
Last month Judge Lance Ito stopped former Detective Mark Fuhrman's boasts of fabricating evidence in other cases from reaching the jury. In so ruling, he found there was no evidence to support the contention that Mr Simpson was framed.
Besides the uncertain motive of racism, why would the police want to frame him? Mr Simpson had entertained policemen at his house and had hired off-duty officers to protect him. The idea that a force which made such a sloppy job of collecting evidence could stage an elaborate operation to frame him, without even knowing if he had a strong alibi, is far-fetched.
For Mr Simpson this waiting will mean more time in his 9ft by 7ft cell, equipped with some of the benefits of celebrity - an incoming-only telephone, an exercise bicycle and a television set.
Racial politics, page 17