From the Guardian, writer Xan Rice describes the brewing tensions.
However, aided by a renewed international engagement over the past two months, the registration process has passed peacefully and smoothly in the semi-autonomous south.
Despite the registration window being extended for a week until today, hopes are high that the vote will still go ahead on schedule.
"Logistical challenges remain but things look to be on track," said John Ashworth, an analyst who works with Sudan's churches. "The momentum is there, and 99% of the international community now say it should happen on time."
South Sudan's right to choose secession stems from the 2005 comprehensive peace agreement, which ended a 20-year civil war between the non-Arab south and the Arab-led north that claimed more than 2 million lives.
Though the peace has held for the past six years, the mistrust between the ruling Sudan People's Liberation Movement (SPLM) in the south and the president Omar al-Bashir's National Congress party (NCP) in the north has not disappeared.
About three-quarters of Sudan's 500,000 daily barrels of oil come from the south, and while this revenue is currently shared between the two sides, the north will lose out if the country splits. Many southerners believe Bashir will try to postpone their bid for freedom to avoid giving up much of the country's petrodollar income.
These suspicions led to many of the southerners living outside south Sudan refusing to register for the referendum, fearing that the Khartoum government will tamper with their votes.
Regardless of what the NCP can negotiate, a divided Sudan will weaken its hand in the north.
Opposition politicians are likely to blame Bashir for the country breaking up, and the loss of a large chunk of oil revenue will also hurt.
This uncertainty has led to some Sudan-watchers to suggest that Bashir would consider using force to prevent secession.
Zan Rice mentioned the revenue sharing agreement for the oil in Southern Sudan. Despite this major settlement there are other issues that would want the north to keep the south from breaking away. Al Jazeera analyzed these issues in the news magazine show "Inside Story'. The video is a half -hour long.
Finally, the organization Operation Rescue has links to the entire NBC Dateline episode that focused on the possibility of civil war, an issue that actor George Clooney has put his stardom into.