The President's announcement is yet another attempt at securing an elusive climate change legacy.
He tried it last summer. It ran into a wall of Congressional opposition.
This time, with the end of his Presidency in sight and with his improved political fortunes, he is setting even more ambitious targets.
The headline figure: The White House wants to reduce carbon emissions from power plants by 32% by 2030 (compared to 2005 levels).
Obama's promotional video tries to make climate change a matter of national security for Americans:
In actual fact, the clean energy revolution means the US is already half way there.
The fracking boom across the country means that natural gas is rapidly displacing coal at power plants.
But the targets will be another boost for America's solar and wind industry.
And the announcement will help America regain the mantle of leadership as the world prepares for the next major climate change conference, beginning at the end of November in Paris.
The political fight over reshaping America's energy economy - underway for years - will now intensify.
Climate change denial is a powerful force in American politics.
Republican Presidential candidates are already lining up to denounce the targets, accusing the White House of trying to destroy the coal industry and of adding an intolerable burden to US business.
President Obama will relish this fight.
He rightly feels science is on his side.
His promotional video, released on YouTube, tries to make it a matter of national security for ordinary Americans by talking of longer wildfire seasons, more violent storms and longer droughts.
It does no harm to the timing of the President's announcement that as he makes the statement at the White House, there are 21 separate wildfires raging in California, incinerating thousands of acres of land.
The severe drought in the Western US has created a perfect storm, and made battling the fires a huge challenge.
Climate change in action?
Or simply the age-old forces of nature?
Either way, it is focusing attention on the President's announcement, and triggering a debate about whether even these new targets are in fact too little and too late to save a wounded planet.