A coalition of business leaders across the state took a major step this week toward asking Colorado voters to raise sales taxes for transportation, but even some who have long supported a tax hike for roads are now questioning whether the effort can succeed.

That uncertainty cast a shadow over Thursday’s long-awaited rollout of four potential ballot measures by the Denver Metro Chamber of Commerce, which is seeking to generate as much as $5 billion for transportation projects.

The proposals would raise the 2.9 percent state sales tax rate by somewhere from a half-cent to a full penny per dollar. But election-year politics and new financial realities have dramatically changed the dynamic from a year ago, when a bipartisan group of lawmakers, business leaders and the governor tried to usher a similar voter-referred tax measure through the state legislature.

Today, Gov. John Hickenlooper is noncommittal. The business coalition that backed last year’s legislation is showing signs of fraying. Republican lawmakers who last year supported a tax hike no longer think one is needed. And even some Democrats who support higher taxes are now questioning whether the options presented by the chamber can be sold to voters.

“The risk that’s being run is this isn’t a bipartisan compromise, there will be opposition and it’s not leaving room for the legislature to work in a bipartisan way to find a meaningful solution to transportation,” said Rep. Alec Garnett, D-Denver, the assistant House majority leader.

He added: “We cannot take the risk and lose in November.”

Bypassing the legislature

No one questions the need. Explosive population growth, coupled with decades of diminishing revenues, have left the state’s roads clogged and craggy. The estimated tab: about $9 billion over the next decade.

Last legislative session, top lawmakers in each party backed a referred measure, House Bill 1242, that would have generated $3.5 billion of that by asking voters to raise the state sales tax by 0.62 percentage points. It died along party lines in a GOP-led committee.

That legislative defeat left Kelly Brough, the Denver Metro Chamber president, looking to bypass the legislature and go straight to the ballot. And she’s confident the effort will succeed.

“I think very clearly … people throughout the state of Colorado strongly believe that you need increased funding to address the level of transportation challenges and needs we have,” she said.

Brough and her supporters haven’t settled on which proposal will wind up on the ballot. Three of them would raise sales taxes by a half-cent, 0.62 cents and 1 cent per dollar, respectively, to generate between $2.5 billion and $5 billion. The fourth would raise taxes by a half-cent and require the state to chip in $150 million of existing revenues annually. Each measure would earmark some of the proceeds for local and regional road and transit projects.

But while the initiatives are similar to last year’s legislative proposal, the enthusiasm for the tax hike has waned. One big reason: Promising revenue forecasts have significantly boosted the political prospects of squeezing road dollars out of the state budget.

Now, the few Republicans who initially supported a tax hike no longer do.

“I don’t think we need the tax increase — we can do it under existing revenues,” said Sen. John Cooke, who chairs the Senate Transportation committee and last year introduced a bill to raise vehicle ownership taxes. Instead, Republicans are rallying behind Senate Bill 1, a measure that would ask voters to finance $3.5 billion in bonds by diverting existing sales-tax revenue from the general fund.

House Democratic leaders have balked, saying the state budget can’t support that much bonding long term without putting the state at financial risk when there’s another recession. But they haven’t yet offered a counterproposal, saying they won’t know how much money there is to spend on roads until updated revenue forecasts are released in March.

Meanwhile, Hickenlooper hasn’t committed to the chamber’s plans, after backing the tax hike a year ago.

“What I’m trying to do is support some sort of a compromise, if it’s possible — I’m not sure it is possible,” he said in an interview earlier this week.

The lack of a consensus on the issue is a problem, he says.

“It’s very, very hard to pass any kind of new revenue,” Hickenlooper said. “So I think the challenge here — and it’s a big challenge — is to how to thread that needle between all the constituencies.”

In search of a united front

There remains broad agreement among business leaders, if not politicians, that new revenue is needed — but many remain unsure of the right path. Some worry the proposed tax hikes are too large for the public to swallow and want more skin in the game from the General Assembly. Others favor alternate revenue streams, such as gas taxes or vehicle ownership fees.

“I think there is just a concern about the political viability, that the residents of Colorado will support a sales tax increase,” said Jeff Wasden, president of Colorado Business Roundtable, an organization involved in the transportation discussions.

Like Hickenlooper, Wasden argues that the business community needs to coalesce behind one option. The conventional wisdom is that convincing tax-averse Colorado voters to say yes will require an expensive public-awareness campaign.

Brough, though, downplays the split in the business community and disagreement on the approach at the Capitol, saying she’s “under no illusion” it would receive broad support from Republicans. And two prominent civic organizations in rural Colorado, Club 20 and Pro 15, are already on board.

“We can’t keep kicking the can down the road,” said Christian Reece, the executive director of Club 20.