A sluggish economy and high gas prices shouldn't derail attempts to get voters to approve a constitutional amendment that would raise the state sales tax and use the money for natural resources and the arts.

So says Ken Martin, campaign director for Vote Yes Minnesota, a coalition of 200 environmental, conservation, outdoors and arts organizations pushing for passage of the amendment on the November ballot.

"I think Minnesotans have shown over time that they are willing to invest in the things they care about in Minnesota," Martin said. "And natural resources and cultural resources are a big part of our quality of life."

While the presidential campaign season might be cranking into high gear, the battle over the constitutional amendment is just getting rolling.

People who attend festivals, parades and other outdoor events -- including farmers markets -- already are starting to see evidence of the campaign.

"Minnesota is not only a land of 10,000 lakes, but it's also the land of 10,000 festivals and fairs, and we're going to try to be at as many of them as possible," Martin said.

It's part of a grassroots effort to garner public support for the measure, which, if approved by voters in November, would raise the state sales tax by three-eighths of 1 percent. That would raise about $270 million annually for 25 years. About 33 percent would go to improve fish and wildlife habitat, 33 percent would go to clean up Minnesota's lakes and rivers, 19.75 percent would go for the arts and cultural heritage and 14.25 percent would go to parks and trails.

Residents will see a full-blown multi-million-dollar advertising campaign in late August or early September, Martin said.

"We'll be able to raise the money we need to compete in the fall and get our message out to voters that we need to win," he said.

The Taxpayers League of Minnesota will mount its own campaign to defeat the amendment, arguing that tax increases aren't needed and that dedicated funding is bad policy, said Phil Krinkie, president of the group.

The league mailed out information last week to supporters. Krinkie said the league will use TV, radio and mailings. And the group's booth at the State Fair will focus on opposing the amendment.

"Don't get hooked on higher taxes, vote no," urges a slogan on the league's website. The theme of the Vote Yes group: "Protect the Minnesota you love."

Sportsmen and conservation groups tried for 10 years to get dedicated funding for natural resources on the ballot before succeeding at the Legislature this year. Supporters argue that funding for natural resources always gets short shrift at the Legislature.

"Over the last 30 years the Legislature has failed to protect the things we care about in the state," Martin said. "The only way we can ensure that over the next 25 years these things are protected is to have a constitutional amendment dedicating funding to these important priorities."

Krinkie disagrees.

"No. 1, it's bad policy," he said. "The Legislature is charged with appropriation of funds. And No. 2, the Legislature just increased taxes by $700 million to $800 million with gas tax, license tabs and increased business taxes. Now you're going to add another $300 million on top of that?"

Martin said the Vote Yes campaign is bringing environmental, conservation and arts supporters together with hunters and anglers in support of the amendment. The Minnesota Outdoor Heritage Alliance (MOHA) and sportsmenforchange.org will play key roles in reaching out to hunters and anglers.

The sportsmen succeeded in getting the Legislature to create a citizens-legislative council to oversee spending of the $90 million in fish and wildlife habitat funds raised by the amendment -- a key sticking point. It was uncertain whether some sportsmen groups would support the measure without it.

Martin said polling by his group indicates broad support for the amendment, and he said he's "cautiously optimistic" it will pass.

"It's going to be a close race, there's no doubt about it, because of the 'drop-off' scenario," he said. Citizens who cast votes in the presidential or senatorial election but "drop-off" and don't vote for or against the constitutional amendment will be counted as "no" votes, under state law.

"The higher percentage of drop-off voters, the harder it will be for us to pass this," he said.

Martin said one advantage is that it appears the constitutional amendment will be on the first page of the ballot, rather than on the back, where some voters could miss it.