On one side were analysts from the Heartland Institute and Heritage Foundation, two climate skepticism groups convinced the Right should never support a tax on the carbon dioxide Americans emit for free.
Theirs is also the position of the Republican Party, whose leaders openly question the science behind global warming, and argue a carbon tax "would devastate an already struggling American economy."
Which is why Andrew Moylan, from a national think tank called the R Street Institute, wasn't certain how the right-leaning Globe Theatre crowd would react to his debate position: that a carbon tax could in fact make the U.S. more prosperous.
"We saw the RSVP list ahead of time," Moylan recounted, "and it didn't suggest the room would be stacked in our direction."
By night's end, Moylan and his debate partner, former Republican congressman Bob Inglis, won the room over.
"We had a show of hands, and there was a pretty large consensus in support of our position," Moylan went on. "Maybe what that says is people agree there's a theoretical case to be made" in favour of a carbon tax.
Climate change denial 'untenable' for GOP
A price on America's carbon emissions will surely remain theoretical for some time. No Republican in Congress publicly supports it. Nor does President Barack Obama. "We would never propose a carbon tax," the White House has promised.
Yet the Globe Theatre debate may signal emerging Republican fissures on global warming. "There is a divide within the party," one conservative scholar recently told the National Journal. "The position that climate change is a hoax is untenable."
And as conservatives such as Moylan and Inglis attempt to widen that divide, by pushing Republicans to embrace a carbon tax, they're looking north to the only jurisdiction in North America that has one: British Columbia.
"It's relatively early days for [B.C.'s carbon tax]," Moylan told The Tyee. "But it's encouraging for those of us who support the idea to be able to point to someplace where it's actually happening."
You could say it's early days as well for Moylan's think tank, the R Street Institute. It was founded just over a year ago by defectors from the Heartland Institute, one of North America's most prominent climate skepticism groups.
Since the late 1990s, Heartland has received more than $600,000 from Exxon Mobil and $55,000 from Koch Industries to question climate science. Last summer, though, it did something "extremely ill-advised" in the opinion of Eli Lehrer.
Lehrer used to head the non-profit group's insurance research team. But he left in May of 2012, when Heartland ran a billboard in Chicago comparing believers in global warming to Ted Kaczynski, the Unabomber.
"A great many people think there is significant risk of climate change," Lehrer told Insurance Journal at the time. "A billboard that says people who believe that this will happen are similar to terrorists withdraws you from rational debate."
The Unabomber ad caused major insurance company backers of Heartland to withdraw their support. Within 24 hours, Heartland pulled the ad down, and called off future billboards featuring Osama bin Laden, Charles Manson and Fidel Castro.
Not long afterwards Lehrer, along with other former Heartland colleagues, created the R Street Institute. "It was largely an amicable split," Moylan said. "Obviously at its core was a disagreement over a major policy issue."
A Cautionary Tale
On the issue of global warming, R Street has for the past year promoted a solution it believes is compatible with conservative values: a revenue-neutral carbon tax, where the proceeds, like in British Columbia, are used to offset other taxes.
"Instead of taxing things everybody agrees are good, like income, investment and entrepreneurship, we should tax bad things like greenhouse gases," Moylan said. "We think that will leave Americans richer in the future."
That remains a minority opinion in conservative circles.
Yet it's one shared by such prominent intellectuals as David Frum, a former George W. Bush speechwriter; Art Laffer, a senior adviser to Ronald Reagan; and Douglas Holtz-Eakin, an economic advisor on John McCain's 2008 presidential campaign.
"There are plenty of folks across a broad conservative spectrum" who support a carbon tax, Moylan said. But he admits, "It's definitely a fledgling group. We are under no illusions that this is going to be an easy fight."
Last November, one of that group's most vocal members, former Republican congressman Bob Inglis, flew to British Columbia to learn more about the carbon tax the province implemented in 2008.
Inglis' story is a cautionary tale for Republicans. The three-term House member from South Carolina helped write a carbon tax bill in 2009. In next year's primary vote, he lost to a Tea Party challenger by 42 percent.
"[My] most enduring heresy was saying that climate change was real, and let's do something about it," Inglis recently said. That conviction brought the former red state congressman to Canada last year.
The Pacific Institute for Climate Solutions had him meet with the B.C. Liberal caucus, eat lunch with then-environment minister Terry Lake, and address the B.C. Business Council in Vancouver.
"In the case of British Columbia, I think you are leading" on climate change, Inglis said during another talk at Simon Fraser University. The U.S., he added, would do well to "follow your example."
Inglis was referring to the province's $30 per ton levy on carbon emissions. A recent Sustainable Prosperity study found the policy helped B.C. achieve big cuts to fuel use and emissions without hurting economic activity.
"B.C.'s experience shows that it is possible to have both a healthier environment and a strong economy," said lead study author Stewart Elgie, a professor of law and economics at University of Ottawa.
Still, Premier Christy Clark's aggressive plans for liquefied natural gas could undo any climate progress made by the carbon tax. And her Liberal government this spring froze the carbon tax rate at $30 for the next five years.
Nevertheless, the policy's basic logic, that revenue from taxing carbon is used to reduce other taxes, is very appealing to conservatives such as Inglis, the Pacific Institute's executive director, Tom Pedersen, told The Tyee.
"[Inglis] looks to the B.C. model as a template for the world," he said.
'Deep internal conflict'
For now Inglis is trying to make the province's carbon tax a template for the U.S. Right.
His efforts place him within a small, but growing, conservative contingent, National Journal reported, fearful that "if Republicans continue to dismiss or deny climate change, the party will become irrelevant."
That "deep internal conflict," the Journal has predicted, could soon cause an outright "GOP civil war over climate change." Nevertheless, it noted, "most Republicans feel much more secure on the side that denies the problem."
Denial of global warming is politically useful. It helps define the Republican Party as "anti-tax and pro-energy" in the eyes of the voting public, argues Marlo Lewis from the right-leaning Competitive Enterprise Institute.
"This clear product differentiation is an asset for the GOP," Lewis has said. "Conservative advocacy of a carbon tax can only blur the battle lines, divide GOP leaders, and demoralize the movement's activist base."
Some green thinkers are also skeptical. Even if conservatives like Inglis and Moylan are successful in getting Republicans to embrace a B.C.-style carbon tax, Grist writer David Roberts is unsure how much good it would do for the climate.
"It's just a fantasy that we can limit global temperature rise to 2 degrees with nothing but a [carbon] tax," he recently wrote. In his opinion fixing the climate demands a massive societal shift akin to wartime mobilization.
But the "large-scale government intervention" needed to enable that shift is anathema to the current Republican worldview. "It is today's hyper-conservatism," Roberts believes, "that is ultimately going to have to change."
Moylan from the R Street Institute agrees that a carbon tax "isn't going to do a tremendous amount in and of itself to reduce global emissions." Even so, he argues, adopting the policy would be an "important symbolic gesture."
More important still: putting a price on U.S. carbon emissions, and then using the revenue to reduce taxes across the country, Moylan believes, "will leave Americans richer in the future."
The "wealthier and more prosperous society" enabled by a carbon tax, he adds, would be better able to pay for the solutions needed to solve climate change, and fix the damages that it causes.
To bolster his argument Moylan looks north to British Columbia. Five years after implementing a price on carbon, emissions there have dropped. So too have tax rates. "Those are definitely some positive signs that we look to," he said.
He's hopeful the Republican Party will someday also see them.