A new poll finds Republican Wisconsin Gov. Scott Walker with a narrowed lead over Democratic challenger Tom Barrett ahead of Tuesday’s recall vote.

A Public Policy Polling survey released Monday shows Walker with the support of 50 percent of likely voters, ahead of Milwaukee Mayor Barrett at 47 percent. 

{mosads}But Walker’s support is down from a 50-to-45 percent edge in the same poll conducted three weeks ago and down from the 7-point 52-45 lead Walker held in a Marquette Law poll released last week.

Barrett leads Walker, however, among independent voters, with 48 percent support to 46. 

Walker holds a net positive approval rating at 51 percent favorable to 47 unfavorable, topping Barrett, who posts 46 percent favorable and unfavorable numbers.

Tuesday’s vote could come down to which side can better turn out supporters.

“What’s going to determine Tuesday’s outcome is pretty simple,” Dean Debnam, president of Public Policy Polling, said in a statement. “If Democrats turn out in the same numbers that they did in 2008, Tom Barrett will win a surprise victory. And if they don’t, Scott Walker will survive.” 

The recall could have implications beyond Wisconsin, as both Republicans and Democrats are seeing the contest as a preview of November’s elections.

A report from the Center for Public Integrity (CPI) released Saturday said the election was the most expensive in the state’s history, with Walker’s and Barrett’s campaigns, as well as outside groups, combining to spend $63 million.

The survey was conducted from June 2 to 3 and has a 3 percent margin of error.