Climate change was not mentioned in the first presidential debate, a striking omission for environmentalists and clean-tech advocates who view it as a lost chance to highlight an issue that is central to the nation's economy and ecology.
The interlinked topic of energy was also overshadowed by the dominant issues of taxes, education and health care in a debate themed around domestic policy. Practiced lines that routinely appear in stump speeches by both candidates received light treatment or were absent altogether, like President Obama's well-worn brags about the toughened fuel economy standards imposed by his administration.
Yet it was the disappearance of climate change that symbolized how much the issue has been disinvited to presidential politics, four years after Obama campaigned on cutting carbon emissions.
"It's just a real shame. What it says about the issue is that it's not a serious political issue," Manik Roy, vice president of strategic outreach with the Center for Climate and Energy Solutions, said before the debate, when asked about the possible omission of climate.
"How would we ever explain to our kids and grandkids 20 years from now that we had a presidential debate this night and did not talk about one of the most important issues facing their world by that time?" he added. "It would be just remarkable if it didn't come up."
From the beginning, the debate's design was violated. The candidates repeatedly surpassed their two-minute allotment of time to answer questions, derailing moderator Jim Lehrer's plan to sweep through consecutive "segments" related to domestic policy. It's unknown if questions about climate change or energy were bumped as time expired on the 90-minute debate.
The debate will be a disappointment for climate advocates, many of whom believe Obama could benefit electorally by rebuking Romney for his shifting assertions about rising temperatures. They viewed the candidates' first face-to-face meeting as a plum opportunity for Obama to set the record straight: Romney saw climate dangers in the past but is now unwilling to tackle them.
"I think if the president brings this up and says, 'I believe in the science and we have an obligation -- moral and, frankly, economic -- to figure out how to deal with this issue,' and questions whether Romney does the same, I think that's advantage Obama," said Roger Ballentine, who chaired the White House Climate Change Task Force under President Clinton.
"And you also play into a serious Romney weakness, which is inconsistency, flip-flopping and political opportunism," he added.
Others had hoped for probing questions from Lehrer. Both campaigns have been setting their own terms for months, appearing before friendly crowds on the trail and dictating when and where to participate in television broadcasts. The debate marked the first opportunity in the race to test the candidates in an unpredictable setting.
But the event failed to yield new information about the candidates' positions on climate, like what steps Obama would take in his second term to drive down greenhouse gas emissions, if he would follow through with a clean energy standard, and whether he would advance efforts to cut carbon in the transportation sector.
Romney might have been asked if it's contradictory to say climate change has negative consequences while pledging to pursue only passive policies to reduce emissions, or why his energy blueprint, which emphasizes expanded fossil fuel production, doesn't mention climate change. Still others anticipated that Lehrer might ask him why he appeared to minimize sea-level rise at his nominating convention, only to acknowledge days later that humans are affecting the climate.
"I could see an interesting question to Governor Romney about some of the evolution of his position on the issue, even very recently," Roy said.
Of Obama, who has been largely silent on climate change, Roy said, "I'd like to know his plans."
The debate didn't reveal those plans. But it did rehash long-standing attacks by both candidates, from Romney's jabs on Solyndra and the Keystone XL oil pipeline to Obama's championing of renewable energy.
"Gasoline prices have doubled under the president," Romney said, pointing out a condition that is driven by market forces more than federal policies. "And by the way, I like coal. I'm going to make sure we can continue to burn clean coal. People in the coal industry feel like it's getting crushed by your policies."
Romney's campaign and his conservative surrogates have aggressively accused Obama of waging a "war on coal." Those messages are being aired in crucial swing states like Ohio and Virginia. Other portions of the nation's coal patch are solidly Republican, raising questions about whether those attacks will harm Obama at the polls.
"It seems like [Obama has] taken a pounding on energy issues in Appalachia," said Kyle Kondik, an analyst at the University of Virginia's Center for Politics. "But he didn't do very well in those places anyway -- southeast Ohio, western PA, West Virginia, western Virginia. There's billboards all over that part of the country with 'Obama's war on coal' and all this other stuff."
Obama, who was halting early in the debate, didn't respond to Romney's coal jab. But his campaign has sought to turn the tables. It released a television ad this week accusing Romney of using coal miners as props during an event in Ohio at a Murray Energy Corp. mine in August (Greenwire, Oct. 3). Miners filled the area behind Romney, a mandatory appearance that forced the company to shut down mining operations.
"Their mine was closed, lost the pay they needed, all to be props in Romney's commercial," the Obama ad says.
There were signs early in the debate that energy issues might rise to the top. Both candidates mentioned it as a top priority in their opening remarks.
Romney acknowledged that oil and natural gas production is growing in the United States -- a claim often made by Obama -- but he credited private producers for the increase, while blaming Obama for limiting energy development on public lands. He proposes expanding production by giving states permitting influence on public tracts, a move that Romney claims can create 4 million jobs.
"I want to get America and North America energy independent so we can create those jobs," he said.
In that respect, analysts say there is only marginal difference in how the candidates envision expanding domestic energy production. But the debate, there, too, failed to uncover details about their plans.
"I would like to see them say more about how we can become more energy independent," Michele Combs, president of Young Conservatives for Energy Reform, said before the debate.
She launched the organization recently to give the conservative movement a voice advocating for renewable energy, strengthened national security and "clean air." She says Romney's energy independence plan is a good "first step" toward using less foreign oil, and she hopes it could lead to legislation in the future that reduces emissions.
The Denver debate might have also missed an opportunity to address sportsmen, a slice of the electorate that tends to be conservative but is concerned about the impact of climate on hunting and angling.
"They've come to recognize for the most part that, yeah, there is something to this," said Eric Washburn, who worked on energy issues under Senate Democrats and is now helping the Bipartisan Policy Center with a project focused on sportsmen. "Now there's not a consensus, I think, around what's causing [climate change]. But I think there's close to a consensus on that the climate is changing, and we're seeing nature shift in ways we didn't see in the past."
Outdoor Life, a popular magazine for sportsmen, issued a voters guide this month that says, "The potential affects of climate change on hunting and fishing have been documented, and the studies aren't coming from enviro-freaks, either."
Two more presidential debates will take place this month. If climate change is absent from those, advocates worry about the prospects of elevating the issue in the national discussion.
"It's certainly a negative for the issue if it doesn't come up. There's no other way to spin that," Ballentine said.