The telephone survey last week found 46 percent favor the constitutional amendment and 36 percent oppose it. Nine percent said they don't plan to vote on the question and 10 percent were undecided.
The amendment would raise the state sales tax by a little less than a half a cent for the next 25 years and dedicate the money to clean water projects, wildlife habitat, parks and trails and the arts.
Larry Jacobs, director of the Humphrey Institute's Center for the Study of Politics and Governance, noted that a constitutional amendment requires the support of a majority of everyone casting a ballot in the election, not just a majority of those voting for the question.
He said the 9 percent who said they'll skip the question are in effect joining the 36 percent who plan to vote "no."
"So at this moment, a fuller report would say that there's actually split opinion about the constitutional amendment," he said. "And it appears that the Minnesota electorate is not sufficiently supportive of this amendment to pass at this point."
A key supporter of the ballot question responded positively to the poll numbers. Ken Martin, campaign manager for Vote Yes Minnesota, said state residents care deeply about their quality of life. Martin said he's working hard to make sure voters don't skip over the amendment question.
"We're cautiously optimistic," he said. "But we know that there's a lot of work to do in the next 27 days. And we need to make sure frankly on this kind of issue we need to make sure that people are aware that this is on the ballot and to look for it if they care about this and want to support it."
Opponents of the constitutional amendment are also out to educate more voters before the election. Phil Krinkie, president of the Taxpayers League of Minnesota, said he's convinced that voters are more likely to vote "no" as they learn more about the dedicated funding measure.
"The Vote Yes people are only talking about the clean water," he said. "They're only talking about wildlife habitat, natural resources. They're not talking about the arts. They're not talking about the tax increase. They're not talking about the 25 years."
Minnesota voters will also decide local legislative contests, with all 134 seats in the Minnesota House up for grabs this year.
The MPR News/Humphrey Institute poll found a distinct advantage for Democrats, driven largely by the economy. Forty-five percent of respondents said they would vote for a DFL candidate, compared to 34 percent who favored Republicans.
If Democrats retain control of the House, they'll have to work with an increasingly popular Republican governor who isn't on the ballot this year. The poll measured the approval rating for Gov. Tim Pawlenty at 61 percent. That's up from 55 percent in August when his name was being mentioned as a possible running mate for John McCain.
The U of M's Larry Jacobs said Pawlenty is bucking an anti-GOP trend.
"We're seeing that he's getting about 40 percent of Democrats giving him strong approval ratings," he said. "Even among those who say that the country is off in the wrong direction, he's getting 57 percent of their support. Now, that is not what we're seeing in most other parts of the Minnesota electorate, where there's a real backlash against Republicans. Gov. Pawlenty seems to be rising above that at this point."
Poll respondents gave their highest marks to Democratic Sen. Amy Klobuchar, who won't be up for re-election until 2012. Sixty-seven percent approved of Klobuchar's job performance, while 20 percent disapproved. She even got the approval of nearly half of the Republicans surveyed.
The poll of 766 likely voters has a margin of error of plus or minus 3.6 percentage points.