The steady trickle of irksomely fustian yet relatively measly climate-change-related regulations, executive orders, grandiose speeches, and frightening studies the Obama administration has been releasing in recent months to quell environmentalist anger have all been leading up to this: The big one.

The EPA will launch the most dramatic anti-pollution regulation in a generation early next month, a sweeping crackdown on carbon that offers President Barack Obama his last real shot at a legacy on climate change — while causing significant political peril for red-state Democrats.

The move could produce a dramatic makeover of the power industry, shifting it away from coal-burning plants toward natural gas, solar and wind. While this is the big move environmentalists have been yearning for, it also has major political implications in November for a president already under fire for what the GOP is branding a job-killing “War on Coal,” and promises to be an election issue in energy-producing states such as West Virginia, Kentucky and Louisiana.

The EPA’s proposed rule is aimed at scaling back carbon emissions from existing power plants, the nation’s largest source of greenhouse gases. It’s scheduled for a public rollout June 2, after months of efforts by the administration to publicize the mounting scientific evidence that rising seas, melting glaciers and worsening storms pose a danger to human society.

“This rule is the most significant climate action this administration will take,” said Kyle Aarons at the Center for Climate and Energy Solutions, one of a host of groups awaiting the rule’s release.

As Politico notes, the timing of this long-planned release isn’t liable to be very helpful for a slew of vulnerable red-state Democrats, and they along with Republicans are going to be touting the shuttered power plants, lost jobs, economic shrinkage, and expensive (some might say, “necessarily skyrocketing“) energy prices that are likely to come from this move for all they’re worth.

And while the Obama administration is looking to this crackdown on existing coal plants as the highest achievement of its climate-change legacy, never fear, greenies: Administration officials are going to keep eagerly occupying themselves with churning out more of those little economically damaging yet, global-warming-wise, ineffectual show maneuvers until the clock runs out, oh joy:

Officials at the Environmental Protection Agency (EPA) are racing to churn out new regulations before the clock runs out on President Obama’s term.

The activity is evidence that Obama’s push to combat global warming with regulation has entered a critical phase, with officials hammering out the details of rules that carry major implications for the environment and the economy. …

The power plants rule has attracted more attention that perhaps any other Obama administration regulation. Industry and green groups have flocked to the White House in hopes of shaping the proposal, slated to be unveiled early next month.

Meanwhile, the administration has convened meetings on agency proposals for regulations involving oil refineries, the renewable fuel standard and a final rule revising regulations for the disposal of solid waste.