(CNN) - Republican Scott Walker appears to have lost his lead in this year's gubernatorial race, according to a new survey of Wisconsin voters.
A Marquette University Law School survey released Wednesday indicated the contest all tied up between the incumbent and Democratic challenger Mary Burke at 46%. That's a significant change from March when the same poll showed Walker up 7 points.
Burke is a former bicycle executive. She's hit Walker's economic leadership that she says left the state ranked 45th in projected job creation, as well as his refusal to accept a federal Medicaid expansion.
Still, as the survey notes, turnout could be key in whether a Democrat can take the state capitol. Democrats historically have struggled to get their base to show up in off election years.
"Turnout is one of the biggest unknowns of the fall election," said Charles Franklin, professor of law and public policy and director of the Marquette Law School Poll.
"Between now and Election Day, some voters will become more engaged by the election, while others may lose interest. These results show that the election outcome can change depending on turnout as both parties seek to mobilize their supporters."
Walker, first elected in 2010, gained national notoriety from conservatives after surviving a recall effort sparked by a budget-balancing initiative that stripped collective bargaining rights from most public unions. After an over year-long battle within the state, Walker beat Democratic Milwaukee Mayor Tom Barrett, 53% to 46% in the 2012 recall contest.
Walker is the first governor to survive a recall.
Even if he does win re-election in November, Walker has refused to commit to serving out a full, four-year term, stoking speculation that he might launch a 2016 bid for the GOP presidential nomination.
The Marquette survey indicated only 27% of Wisconsin voters would like to see Walker run for president, while 67% would not. Unsurprisingly, half of Republicans would like to see him run, compared to 9% of Democrats in the state.
The Marquette poll was conducted from May 15-18 with 802 registered Wisconsin voters questioned by telephone. The poll's sampling error is plus or minus 3.5 percentage points.