THE NATIONAL debate on climate change has devolved.

By the late 1990s, big U.S. businesses were beginning to accept that greenhouse gases must be wrung out of the economy. In the 2000s, prominent Republicans such as Sen. John McCain (Ariz.) and Gov. Mitt Romney (Mass.) proposed aggressive anti-emissions policies. By 2008, the presidential candidates of both major parties favored strong national climate strategies. Regardless of who won that election, serious action seemed inevitable.

But Republicans later embraced a strategy of rote opposition to President Obama, and a faction that rejects the science of global warming dragged the GOP into irresponsible head-in-the-sand-ism. Democrats, meanwhile, proved unable to unite around a coherent, comprehensive climate strategy when they controlled Congress and the White House.

Strong underlying political currents help to explain Washington’s failure. Voters generally don’t put climate change high on their priority lists, and there is evidence that some Americans’ belief in the science varies with the weather. Party politics often push in a negative direction: GOP primary voters are more likely to punish a vote for a climate plan than to reward one, while Democrats’ position in Congress depends on winning races in coal states such as Ohio, Pennsylvania and West Virginia.

Some of the Democrats who voted for a large 2009 cap-and-trade bill lost their seats in the 2010 midterm election. Though that election turned more on the state of the economy and on health-care reform than it did on climate change, the voter rebuke recalled the previous Democratic effort to raise the price of energy: the infamous BTU tax debate, which contributed to the 1994 Republican midterm wave.

So these days Republicans mostly ignore the issue or offer excuses for doing nothing: The science is not reliable; anti-emissions policies will harm the economy; China and India will continue emitting even if the United States cuts back. Many Democrats and environmental activists, meanwhile, focus on relatively inconsequential — but potentially winnable — battles, such as their push to reject the Keystone XL pipeline .

But there are reasons not to give up. The biggest is the urgency of action. As the U.S. debate has deteriorated, scientists’ warnings have become more dire. According to the authoritative Fifth Assessment Report of the Intergovernmental Panel on Climate Change , every region of the world faces serious risks , including sea-level rise or worsening heat waves, floods and wildfires — and those are consequences scientists can predict. Though poor nations along the equator may be hit hardest, U.S. analysts are beginning to quantify a variety of direct and negative effects climate change could have in our own country .

These factors help explain a second reason for hope: Despite ups and downs in the polling, a solid majority of Americans favors action to curb greenhouse emissions. As with the recent national shift on gay marriage, feelings on climate change will eventually move more decisively — we hope in time to spare the world unnecessary expense and suffering.

And the United States is reaching a put-up-or-shut-up moment. As Congress dithered, Mr. Obama filled the policy void with executive actions designed to cut greenhouse emissions under authorities Congress entrusted to the Environmental Protection Agency decades ago in the Clean Air Act.

The EPA’s rules are a decent and, under the circumstances, necessary first step, but they would not cut emissions enough over the next century. And, for all of their benefits, they represent a cumbersome and expensive way to slash emissions. As full implementation looms, industry may press for more efficient policies that sting companies and consumers less, and Republicans may be willing to countenance market-based approaches to the climate problem.

All this explains why, understandable frustrations notwithstanding, the shape of the climate debate now and through the 2016 election is important. In the coming days we aim to contribute to that debate with a brief series of editorials. We will review the need to act; defend the EPA’s efforts but explain why they are not ideal; highlight several strategies that would work better; and show why it makes sense for the United States to take steps even though other nations have yet to do enough on climate change.

Action of some kind, at some point, is inevitable. Our proposition is that it should come sooner rather than later and be smart rather than clumsy.