WASHINGTON — Democrats say President Barack Obama’s aggressive campaign will be built around executive powers to sidestep congressional opposition.

“We will respond to the threat of climate change, knowing that failure to do so would betray our children and future generations,” Obama said Monday at the start of eight sentences on the subject, more than he devoted to any other area.

“Some may still deny the overwhelming judgment of science, but none can avoid the devastating impact of raging fires and crippling drought, and more powerful storms.”

The central place he gave to the subject seemed to answer the question of whether he considered it a realistic second-term priority. He devoted scant attention to it in the campaign and has delivered a mixed message about its importance since the election.

Obama is heading into the effort having extensively studied the lessons from his first term, when he failed to win passage of comprehensive legislation to reduce emissions of the gases that cause global warming.

This time, the White House plans to avoid such a fight and instead focus on what it can do administratively to reduce emissions from power plants, increase the efficiency of home appliances and have the federal government itself produce less carbon pollution.

The centerpiece will be action by the Environmental Protection Agency to clamp down further on emissions from coal-burning power plants under regulations still being drafted — and likely to draw legal challenges amid criticism by conservatives that such changes would cost jobs and leave the United States less competitive.

The administration plans to supplement that step by adopting new energy efficiency standards for home appliances and buildings, a seemingly small advance that can have a substantial impact by reducing demand for electricity.

The Pentagon, one of the country’s largest energy users, also is taking strides toward cutting use and converting to renewable fuels.

The president’s aides are planning those steps in conjunction with a campaign to build public support and head off political opposition in a way the administration did not do the last time around. But the White House has cautioned environmental activists not to expect full-scale engagement while Congress remains occupied by guns, immigration and the budget.