(CNN) - With just under three weeks to go until the recall election of Wisconsin Gov. Scott Walker, a new poll indicates that the Republican governor holds a six point advantage over his Democratic challenger.
And, while the race remains close, there is one thing on the rise: ad spending.
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According to a Marquette Law School poll released Wednesday, 50% of people likely to vote in Wisconsin's June 5 election say they back Walker, with 44% saying they support Milwaukee Mayor Tom Barrett, and three percent unsure. The Democratic candidate won his party's primary last week, setting up a rematch with Walker from the 2010 election, that Walker won by five points.
Walker's 6-point advantage in the new poll is up from a one point 48%-47% margin over Barrett in a Marquette Law School survey conducted last month.
Republican Lt. Governor Rebecca Kleefisch also faces a recall election. The poll indicates she holds a 47%-41% advantage over Professional Fire Fighters of Wisconsin President Mahlon Mitchell in that recall election, with 10% undecided.
Walker set off a firestorm in January 2010 when he moved to curtail the collective bargaining rights of most Wisconsin state employees.
With majorities in both houses of the legislature, Walker and his GOP allies voted to limit raises for public employees except police and firefighters to the rate of inflation, bar unions from deducting dues from workers' paychecks and force them to hold a new certification vote every year. That bill was signed into law in March, following weeks of protests at the state capitol building in Madison.
Republicans insisted it was necessary to control the skyrocketing costs of public employee benefits and close the budget shortfall. Democrats argued it was an attempt to gut public-sector labor unions, one of their core constituencies.
The public demonstrations all but shut down the Wisconsin state legislature for weeks. It also drew protesters by the tens of thousands, among them union supporters and public employees, who called the measure an attack on workers. A group of Democratic lawmakers left the state for some time in an effort to not allow a quorum for a vote.
The state Supreme Court upheld the controversial law in June, but the battle sparked a storm of political activism that led to the recall effort. The election was scheduled earlier this year, after more than 900,000 signatures petitioning for a recall of the first-term governor were collected.
This would be the first time in Wisconsin's history that a governor has faced recall. There have only been two successful gubernatorial recalls in the nation's history: California Gov. Gray Davis in 2003 and North Dakota Gov. Lynn Frazier in 1921.
Big bucks are being raised and spent in the recall effort. Both tea party groups and other grassroots and fiscal conservative organizations on the right, and labor groups and progressive organizations on the left, as well as the campaigns and Democratic and Republican party committees, have been pouring in money to build up get out the vote efforts, and to put up TV commercials.
According to Kantar Media/Campaign Media Analysis Group, which tracks political ad spending, nearly $11 million has been spent from the beginning of November through Monday to run recall television commercials in Wisconsin.
"The amount of spending is especially impressive given the compressed schedule for the recall and the fact that Wisconsin has just one expensive media market, Milwaukee, CMAG Vice President Elizabeth Wilner tells CNN. "Recall advertisers have basically road-blocked the airwaves to such a degree that presidential advertisers are steering clear, despite Wisconsin being a battleground state."
And with just under three weeks to go until the recall contest, expect ad spending to soar even higher.
The Marquette Law School poll was conducted May 9-12, with 600 likely Wisconsin recall election voters questioned by telephone. The survey's sampling error is plus or minus 4.1 percentage points.
CNN's Gregory Wallace contributed to this story