Democratic presidential front-runner Hillary Rodham Clinton pledged Sunday that if elected she will build on a new White House clean-energy program and defend it against those she called “Republican doubters and defeatists.”

Clinton was the first 2016 candidate to respond to the ambitious plan that President Obama will debut on Monday. Details of the program, which aims to cut greenhouse-gas pollution, were released over the weekend. The new regulation will require every state to reduce emissions from coal-burning power plants.

In a statement Sunday, Clinton called the plan “a significant step forward in meeting the urgent threat of climate change.”