By Brendan O'Brien
(Reuters) - Republican Governor Scott Walker's lead widened slightly over Milwaukee Democratic Mayor Tom Barrett in the run-up to the Wisconsin recall election, according to a poll on Wednesday that showed almost all Wisconsin voters have made up their minds.
The Marquette Law School poll showed Walker had a 50 to 44 percent lead over Barrett, who lost by a similar margin to Walker in the 2010 governor's race. The recall vote is June 5.
Only three percent of likely voters are undecided, according to the poll conducted from May 9 to 12. The extremely low number of undecided voters is unusual in a month-long campaign.
Two weeks ago, the same survey showed Walker with a 48 to 47 percent lead over Barrett, who at the time, was in a primary battle with three other Democrats.
No poll has shown Barrett in the lead since the Democratic primary election was held on May 8.
Walker saw a slight improvement in support despite the emergence of a video that showed the governor talking in early 2011 to a supporter about his strategy to "divide and conquer" the state's public sector unions.
Democrats said the video was further proof that Walker had a secret plan to battle unions. Walker said he was only trying to explain that he wanted to take give control over state finances back to taxpayers.
"In a close election with so few undecided voters, enthusiasm, turnout and campaign contact with voters may make the difference," Marquette Law School Poll Director Charles Franklin said.
Walker infuriated Democrats and labor organizations weeks after taking office in 2011 by driving a measure through the Republican-led legislature to curb the collective bargaining powers of public-sector unions.
The law required many employees to pay part of their health insurance and pensions, capped wage increases to inflation and required unions to hold member votes yearly to stay certified. The proposals set off massive protests at the capital in Madison.
Walker's opponents submitted more than 900,000 recall petition signatures to the state elections board in January, triggering a vote on whether he should remain in office.
On the campaign trail and in television advertisements, Barrett has focused on Walker's job performance record, attacking him on weak job growth throughout the state during his first year in office.
They also have hit Walker on job creation, pointing to official statistics that show Wisconsin lagging behind most other states. Walker has pledged to create 250,000 jobs during his four-year term.
On Wednesday, Walker aides released the state's Quarterly Census of Employment and Wages data, which suggests an increase of 23,321 jobs in the state between December 2010 to December 2011. The quarterly census is a seldom-used measure of job growth. Most economists look at monthly data from the U.S. Labor Department.
The law school poll surveyed 704 registered voters, 600 of whom are likely voters. The margin of error for the survey involving likely voters was 4.1 percent.
(Reporting by Greg McCune; Editing by Jackie Frank)