PRINCETON, NJ — U.S. registered voters remain split on whether President Obama deserves to be re-elected in 2012, with 46% saying he does and 51% saying he does not — little changed from earlier this year. The most recent Obama re-elect measure is similar to the president’s basic job approval rating among all Americans, which was 50% in the June 11-13 USA Today/Gallup poll and 48% in Gallup Daily tracking for the same period.