CO2 emissions: Obama's war of choice
There are, they say, wars of choice and wars of necessity. President Obama has embarked on a war of choice - one that will delight some Democrats but could cost others dearly.
Republicans claim it is a "war on coal", a toxic mix of executive overreach and dogma.
Supporters will say he is finally living up to his promises to do something about global warming and pollution.
But what is interesting is the way that he is selling it.
He's not urging Americans to save the planet, but to save their kids.
Listen to the Environmental Protection Agency's administrator Gina McCarthy.
"This is not just about disappearing polar bears or melting ice caps, this is about protecting our health and our homes," she said.
She's almost sneering at environmentalists, claiming the new rules are not about some wishy-washy, goody-goody desire to save the beasts and the birds but about you. President Obama spoke last week at a hospital for asthma, and he's talking today to those concerned with fighting lung disease.
For years politicians have been warning of the dire effects of global warming. Rising seas will cause cities to disappear, they said, chaotic weather pattern will flatten towns, lack of food, water and land will lead to wars and conflict around the globe. Tony Blair tried to use the argument to give the European Union a mission. David Cameron hauled it in as a badge of his party embracing the modern age. It was meant to be what would get young people re-engaged in politics.
But here in the US, many seemed unconvinced and unmoved. It has perhaps been the big mistake of the environmental movement to talk about "saving the planet" rather than saving those who live on it. People may not be willing to wear a hair shirt, or even a hemp one, for Gaia, but they may make some sacrifices to stop their child's cough (even if it is more likely to be cause by pollution from cars than power stations).
It is what has happened in China, after all. Even top party officials have to breathe the same air on the streets and action is being taken - slowly, late perhaps, but there is movement.
The appeal to self interest is the core of Obama's message as the EPA proposes cutting emissions by a third in 15 years.
It is still a big risk for Obama's party, if not for him personally.
Many of his critics don't accept that global warming is the result of man-made carbon emissions, so they just don't think the caps are necessary.
I suspect some, including many people who are not very political and who parrot this argument, just don't care very much - despite all the dire warnings, they don't think it will affect them, and they would rather have cheap energy and less fuss.
The appeal to children's health is tailor-made for them.
The industry is already warning that these plans are America's next energy crisis in the making.
According to one insider I was talking to recently, the power industry will warn the lights could go out if coal-fired power stations are forced to close.
It may help to ignite the base in other states.
But the president's thinking probably isn't about this year's mid-term elections. In 2007, he warned that the planet was in peril and many environmentalists enthusiastically saw the policy of this potential president as "aggressive".
Whilst in office, President Obama's environmental ambitions have taken a battering.
It would be difficult for him to leave office having done nothing about a problem he believes threatens the world - and America's children - even if it costs some Democrats votes.