When the Denver Regional Council of Governments decided four years ago to allow more development in the territory it managed around the Denver-Boulder metropolis, the move was hailed by supporters as a reasonable necessity to give the fast-growing area a little more breathing room.

The Urban Growth Boundary was established to prevent the unchecked growth of car-centric development. But after decades of breakneck suburban sprawl, some argued that the limits inside the perimeter had become a little too restrictive. The region’s population is nearly 3 million today — a surge of more than 24 percent in the past 10 years — and all of those people must live, work and shop somewhere. They all want schools, parks and other municipal amenities. They all want roads that are wide and new and plentiful enough to speed them along. And all of that construction is gobbling up more and more open space along the Front Range of the Rockies.

But groups such as Environment Colorado cried foul. “Slowly,” the grass-roots organization quipped in a written statement, “the UGB is becoming a UGS (Urban Growth Sieve).”

So it goes for the politics of smart growth in the Centennial State: There are fits of progressive-style conservatorship followed by starts of regulatory peel-back.

Though the national housing crash and economic decline have slowed urban growth and suburban expansion across the United States, states like Colorado still face serious long-term questions about how to best manage growth. By the council’s own estimates, the City of Denver will have at least 700,000 residents by 2035 — which would be a 17 percent increase since the 2010 census. Suburban counties are set to experience even more dramatic growth, with populations in some of them expected to more than double in that period.

So while the national political lens zeroes in on 2012 and its overarching focus on the economy, many Coloradans are keeping a close eye on how politicians plan to handle growth once the recession is over. “Environmental politics brought a lot of new voters into the fold over the last decade,” said Eric Sondermann, a political analyst and principal at SE2, a Denver communications and strategy firm. “While the economy is, like it is everywhere, the big driving factor for 2012 voters, there are still Coloradans who really care about these kinds of issues.”

And for the presidential candidates aspiring to secure Colorado’s nine electoral votes, that’s something to keep in mind. Because along the Front Range, where about 60 percent of the state’s residents live, the business of growth has gotten big. In the years since the regional council allowed more development, all sorts of proposals for projects have been unveiled, despite the national real estate swoon and the subsequent recession. Not all of them were about creating new neighborhoods; some called for entirely new cities.

Sterling Ranch’s Fate

How a president can shape the growth of the suburbs and the strengthening of inner-city economies is more than anything else about his transportation policy and his ability to get Congress to bend to his will on how to spend about $50 billion on highways and another $8 billion or so on mass transit. Obama has pushed hard, albeit with limited success, for curtailing spending on roads and bridges in order to increase the money available for buses, light-rail lines, bike paths and — most controversially — high-speed intercity train service. All of his potential Republican opponents have essentially embraced the notion that federal policy should preserve the passenger car’s standing as the most culturally important consumer product of the past century.

And so whether Obama is re-elected or replaced will go a long way to deciding the fate of a project such as Sterling Ranch, in which 3,000 acres of mountain-nuzzling Colorado prairie would be transformed into a full-fledged bedroom community of 31,000 people — with new schools, retailers and all the other trappings of suburban life. The site is 30 miles south of Denver, where some of the region’s most robust growth has already taken place; the Douglas County population soared by 53 percent in the past decade and now stands above 288,000. As a result, federal taxpayers just recently finished paying for new lanes on Interstate 25 and an extension of a rail line into downtown. But those improvements stop just short of where Sterling Ranch would rise; without tens of millions of dollars in new federal spending, potential homebuyers would need to accept the notion of a longer-than-two-hour daily commute. And the collective carbon footprint of all those slow-moving cars would more than offset the “green” amenities promised by the developers — including a special rainwater conservation system and a layout designed to promote walking and discourage short car trips.

In the past 10 years, the drive for “smart growth” was a “contributing factor to Democrats getting a more solid base in Colorado,” Sondermann said. “Along with social issues, that’s helped turn the state from solid red to more of a purple.”

As recently as 2004, the GOP held the governorship, both halves of the General Assembly and seven of the state’s nine Congressional seats. The partisan tide began to turn that year when Ken Salazar, who was then state attorney general, won an open Senate seat. Today, the governorship and state Senate are in Democratic hands, as are both Senate seats and three of seven House seats. And Obama has a solid shot at repeating his success of 2008, when he was the first Democratic nominee to carry the state since 1992.

But last year’s GOP resurgence illustrates the tenuous partisan balance in the state. Republicans won back the secretary of state and state treasurer jobs and picked up two House seats but came up 29,000 votes (about 2 points) short of taking back a Senate seats in one of the nation’s most expensive Congressional contests. Democrat Michael Bennet, appointed when Salazar became Interior secretary, bested Ken Buck, a rural county prosecutor and tea party favorite. His rejection of the notion that human behavior is contributing to global warming may have cost him decisive support in the swing-vote suburbs.

But a look at how Democratic Gov. John Hickenlooper won his race shows the complications of running statewide in Colorado on issues relating to transportation and growth — especially during times of economic malaise and concern about the growth of government. Though his campaign material touted support for “multi-modal and sustainable transportation platforms” — including options such as bicycle-sharing programs, which he brought to fruition in Denver when he was mayor — it also echoed one of the year’s most frequent conservative calls, that the state should “get out of the way” of business by imposing fewer requirements.

As the Obama administration prepares for 2012, it has sent a series of mixed signals to Coloradans when it comes to how government might step in to shape the look of future growth in the region.

Authorities in Colorado established the Rocky Mountain Rail Authority to seek federal money to study the feasibility of high-speed rail service in the state, a goal that would seem to dovetail the president’s efforts to start work on a series of intercity bullet trains. But budget realities have hit Obama’s plan hard: The transportation spending package for this fiscal year, enacted last month, provides no money at all to advance the president’s plans. (For Coloradans, that means that for at least the next year, there will be no work to advance Obama’s concept of a superfast train between Denver and Santa Fe, N.M.)

But Congress did retain some growth provisions that the president likes in that spending law — including maintaining (over sustained Republican objections) a steady source of federal money to construct no-cars-allowed transportation alternatives such as bike paths and hiking trails.

A Tenuous Partisan Balance

While the president’s team has made clear that he’ll make every effort to carry Colorado again next year — he’s been twice already this fall — the highest-ranking person from the state in his administration, Salazar, has received mixed reviews among Democrats in Colorado. His critics say he’s abandoned much of his bite on environmental issues, one he sharpened during his 2004 campaign for Senate, which he declared as “fighting for Colorado’s land, water and people.” The Interior Department came under fire for its response to the BP oil spill in the Gulf of Mexico and for what some criticized as lax review processes for permitting deep-water oil wells. And advocacy groups such as Defenders of Wildlife have dinged Salazar and the administration for lightening endangered species protections for animals such as the Rocky Mountain Gray Wolf.

But how much of an effect those decisions will have on Colorado’s presidential politics next year remains to be seen. None of the GOP contenders have thus far laid out significant growth or environmental policies, though most have rhetorically lashed out against federal bureaucracies including the Environmental Protection Agency. Republican strategists in the state say they’re not expecting that to be a big problem in courting Coloradans, betting instead that voters — and especially the Republican base — are most acutely concerned about the need to jump-start the economy.

And with the state’s caucuses set earlier than ever, on Feb. 7, they’re banking that the party faithful will make their choices based on what the candidates have said in New Hampshire, Iowa and South Carolina.

But that won’t stop Democrats from seeking leverage with independent voters, many of whom have concerns about how the state’s explosive growth will play out over the long term. One of the country’s hottest House races next year is likely to be in a newly redrawn suburban Denver district, where Democrats think state Rep. Joe Miklosi can win the bulk of the independents and deny Republican Rep. Mike Coffman a third term. By the time the winner is on the ballot again in 2014, he will be representing several thousand new homeowners in Sterling Ranch. Construction on the development is scheduled to begin in earnest early next year.