Paul Portz marches into a cul-de-sac, a green crusader on a mission.

With his little dog, Rico, under one arm and a "Save Par 3" sign under the other, he's drumming up support to buy an ailing golf course in Mendota Heights.

Portz plunges the sign into a lawn. "Good job, Rico," he says to his shivering pooch. "We are really starting to gain momentum."

Indeed they are. At an accelerating rate, Minnesota voters are passing open-space measures - buying land not to use for any purpose but to prevent the construction of homes and businesses. The success rate for such votes is surging - about 83 percent have passed in 20 years. That is more than twice the success rate, for example, of school funding measures in 2006.

Yet by most standards, the metro area is awash in open space.

The Metropolitan Council says there are 182,000 acres of developed open space, classified as "parks, recreation and preserves." This has increased 47 percent since 1990 - and is now equal to twice the area of St. Paul and Minneapolis combined.

Then there is another million acres of undeveloped land, including farmland.

The total? Open space covers 65 percent of the metro area.

That's one reason why the Twin Cities has the fourth worst sprawl of metro areas in the country, out of the top 25 largest cities. It is more sprawled than cities such as Los Angeles and Houston.

Yet open-space measures keep on passing. "Minnesotans love the land," said Jane Prohaska, director of the Minnesota Land Trust, a booster of many open-space efforts.

Critics say the movement reeks of environmental hypocrisy.

Open-space votes are sold as Earth-friendly measures. Yet they add to sprawl, pollution, traffic congestion and the tax burden on Minnesotans, say officials who are joining a green backlash.

"How much is enough?" snapped Mel Mettler, mayor of Columbus in Anoka County, where the open space covers 40 percent of the city. "Maybe we should all just leave here and let the animals have the whole city.

"We are sprawling more and more. Does anyone ever add up the county, state and federal parks? Who is keeping track of this?"

BALLOT-BOX WIZARDRY

At the ballot box, open space is pure magic.

Even tax-averse Republicans in suburbs will open their wallets to save areas they believe are precious, said Minneapolis pollster Bill Morris, owner of Decision Resources.

Minnesota voters have passed 24 out of 29 open-space measures since 1988, spending a total of $632 million. Nationally, over the last nine years, more than 77 percent of open-space measures have passed for $27 billion, according to the Trust for Public Land.

"There is nothing that passes more," said Morris. "There is real momentum here."

He said the measures pass in fast-growing areas because they are presented as a one-time opportunity to "save" an area from development.

But his research shows a curious inconsistency.

"We ask them about sprawl, and they say that is bad," said Morris. Yet voters won't support solutions to sprawl - such as developing land.

Morris said it usually doesn't matter what the land is. It could be a swamp, farm or a golf course. What matters is that there are no homes.

"They pretty much say green space is good," shrugged Morris.

WHAT FEELS RIGHT?

Parks - like roads or schools - serve a need that can be measured. At the rate that people normally walk, play and relax, the standard guideline is 10 acres per 1,000 residents, according to the National Recreation and Parks Association.

But the open-space movement defies that logic.

There are no standards for open space, because it serves no purpose that can be measured. It is based on what feels right to a community - which opponents find maddeningly vague.

"It's what the community perceives as a value to it," said Randy Oppelt, Burnsville's Parks and Public Works director.

He is proud that his city has five times the number of parks called for by national guidelines, in addition to undeveloped open space.

Open space isn't supposed to be accessible to the public, he said, but it still has value: It's attractive and maintains the city's rural character.

"It's to create a feeling when you drive to work," said Oppelt. "When you drive down the street, it's not house, house, business, house. It's house, pond, lake, grass, open space, house."

Oppelt said building on the open space would combat sprawl, but it would be ugly.

"Sprawl is a balancing act," said Oppelt.

Experts say open space is only one factor in sprawl, along with cheap gas and expensive land. Minnesota geography is a factor, because it's less efficient to build cities around lakes and rivers than on a featureless plain.

Multi-acre home lots - think Afton or West Lakeland Township - were another villain, said Cordelia Pierson, program manager for the Minnesota branch of the Trust for Public Land.

"That is the worst outcome for natural resources and quality of life," said Pierson. "Everyone has a back yard, but there is no place to come together."

But open-space measures are the only cause of sprawl that people vote on.

"Voters see them as strongly supporting the protection of water, wildlife and natural areas. They closely connect this to quality of life," said Pierson. She called support for open space the "No Child Left Inside" movement.

Prohaska, of the Minnesota Land Trust, said even if open space contributes to sprawl, it boosts the quality of life for nearby residents, if not for commuters.

"No one would claim that protecting the lakes in Minneapolis adds to sprawl," said Prohaska. "It's a combination of finding places we love and then protecting them."

STOP THE SPRAWL

But if Minnesotans love the land, they should stop gobbling it up, say critics.

They say campaigns for excessive open space share a problem with other environmental causes: Local decisions have global consequences.

People want open space near them but don't see that "saving open space" just consumes it somewhere else, said Michael Noonan, president of the Builders Association of the Twin Cities and division president of luxury home builders Toll Brothers Inc.

If land is rendered unbuildable, builders just move to more outlying areas. The metro area spills outward, lengthening commutes, choking highways and increasing pollution.

The results can be seen in any traffic jam.

"Just stand at the edge of Maple Grove in the morning and see all the headlights coming towards you from St. Cloud," said Noonan. "That is a direct result of limited land supply."

He said some open-space efforts ignore key benefits of development to taxpayers and homebuyers. Several experts said it was hypocritical for newcomers to move to a rural area and then declare that no one else could do the same.

"They don't want people like them moving into a $900,000 McMansion," said Bob Bonine, who is heading an effort to defeat the Mendota Heights golf course measure.

Open space doesn't generate taxes, but homes do. Bonine said the proposed houses on the Mendota Heights golf course would yield $160,000 a year in new taxes.

That is one reason it's poor policy to buy land not needed for public purposes, said Dr. Kelly Cain, a professor of environmental science at the University of Wisconsin-River Falls.

"The idea that most land should be in private ownership is a fundamental value in America," said Cain. "At what point does that become an abused power?"

Mayor Mettler says that point has been passed.

Columbus is dominated by the Carlos Avery Wildlife Management Area, a 20,000-acre plot twice the size of Maplewood. That wasn't big enough, the Trust for Public Land argued recently. The group wanted to add another 160 acres.

Mettler balked.

"Do you just go for this Pac-Man mentality and keep taking chunks out of the city?" he fumed.

Mettler would like to see development but feels besieged by an insatiable open-space movement. "Where do you draw the line between where animals live and where people live?" he asked.

'LOOK BEYOND NUMBERS'

On the pampered lawns of Mendota Heights, the debate is being waged with signs.

About 15 of Bonine's anti-golf-course signs had been stolen from lawns as of Wednesday, but he was confident of victory.

He said the city's 28 percent open space is enough, including 13 parks, two other golf courses and the Dodge Nature Center. The city doesn't need to spend $2.8 million for a 17-acre golf course, he said.

"They talk about preserving this little jewel. Wrong," said Bonine. "We have a surplus of open space."

But along the golf course, looking at the row of houses with "Save Par 3" signs, it's hard to believe history won't repeat itself.

"It comes down to quality of life. Do we want another 19 homes, or do we want something special?" said Sally Lorberbaum, co-chair of the Save Par 3 Committee.

How much is enough open space? "I don't know if there is a number. We need to look beyond numbers," said Lorberbaum.

Last week, she spotted the ultimate endorsement.

"The children wrote 'Save Par 3' with chalk on a driveway," said Lorberbaum. "It speaks to the quality of residents we have here."

Bob Shaw can be reached at bshaw@pioneerpress.com or 651-228-5433.