PPP predicted the amendment would pass by 16 percentage points.
"The final yes percentage will likely be somewhere in the 57-59 percent range depending on how the undecideds break," PPP offered in a news release.
Meanwhile, the latest polls show Bob Etheridge closing the gap on Lt. Gov. Walter Dalton in the race for the Democratic nomination for North Carolina governor.
Every poll showed the contest as a battle between Dalton and Etheridge with the rest of the field running far behind.
Last week, a Public Policy Polling poll showed Dalton was cruising with a 10 point lead. Now, however, it's a different story. This week, Etheridge cut the gap in half and, figuring in the margin of error, it could be a dead heat.
Read the full poll at: http://www.publicpolicypolling.com/main/2012/05/final-nc-primary-poll.html
Polls are open Tuesday from 6:30 a.m. to 7:30 p.m.