What’s a larger lapse in leadership, refusing to admit that the country has a problem, or acknowledging the problem and refusing to tackle it?

That question emerges from Wednesday’s GOP debate, in which Florida Sen. Marco Rubio took offense at the notion that he is a climate “denier” but nevertheless led his fellow Republicans in condemning “left-wing” plans to address climate change.

“We’re not going to destroy our economy the way the left-wing government that we are under now wants to do,” Rubio declared. New Jersey Gov. Chris Christie piled on, warning against the “wild left-wing idea that somehow us by ourselves is going to fix the climate.” Wisconsin Gov. Scott Walker attacked the Environmental Protection Agency for allegedly endangering tens of thousands of jobs in its quest to reduce greenhouse gas emissions.

Not everyone on stage followed this script. Kentucky Sen. Rand Paul tried to break into the conversation: “If you want a skeptic, Jake, I will happily jump into that briar patch.” Thankfully, the moderators shut him down for speaking out of turn, and others on stage who might have attacked scientists weren’t called on.

But the resulting conversation wasn’t much better. The message of the evening was: Climate change may be happening, but shame on those trying to address it.

In fact, the EPA estimates its carbon dioxide rules would cost $5.1 billion to $8.4 billion in 2030. Even if they are off somewhat, numbers of that size do not threaten a $17 trillion national economy. Rubio also argued that the country will reap no benefits from acting because the United States can’t solve climate change by itself.

But the United States isn’t acting alone; its leadership is prompting action from other countries, which will meet in Paris this year to pledge specific carbon-reduction goals. As with free trade, the way to coax other nations to move is for the United States to show willingness to move. Rubio condemns U.S. politicians who would fail to lead other nations, but he excuses himself from that responsibility on this issue.

If the candidates had any good alternatives to President Barack Obama’s climate agenda, they didn’t let on. Christie bragged about one of his worst decisions as governor of New Jersey, pulling the state out of the Regional Greenhouse Gas Initiative, a market-based agreement among states in the Northeast and Mid-Atlantic to reduce carbon dioxide emissions. He claimed that his state still kept emissions down by using nuclear power and burning natural gas. But nuclear power is expensive and the nuclear fleet is aging. Natural gas, meanwhile, has been a success story but still produces significant greenhouse emissions and can be only a bridge to newer and cleaner energy technologies.

True conservatives would recoil from picking winners and losers in the energy debate and instead embrace the policies Christie attacked — market-based, technology-neutral plans that cut emissions while maximizing individual choice and minimizing costs.

Should we be grateful that some Republicans have moved from junk science to junk policy? Sadly, they remain on the reckless fringes of the debate, which is not where any credible candidate for president can be.

Editorial by The Washington Post