In a video posted to the White House website over the weekend, Obama said his address to Americans from Georgetown University will include details of a "national plan to reduce carbon pollution" and efforts to "prepare our country for the impacts of climate change."
He will once again reiterate his desire to spark an American clean energy economy by creating the next generation of biofuels and “new sources of energy.” The president also said he'd call for businesses, scientists, engineers and farmers to take a leading role.
New restrictions on greenhouse gas emissions from existing power plants — a pet cause of the powerful Environmental Protection Agency — as well as new efficiency standards for energy use are likely to be among Obama's centrepiece proposals.
The president is expected to achieve many of his objectives through executive orders. That's because Republicans control the U.S. House of Representatives and have enough might in the Senate to mount legislation-killing filibusters.
Previews of the speech reportedly contain nary a word about Keystone XL, arguably the biggest environment-related headache to vex the Obama administration over the past five years. For a second time, the U.S. State Department is currently assessing the $7.6-billion pipeline because it crosses an international border; an ultimate decision isn't expected until at least the fall.
One rising climate leader in Congress, Sen. Sheldon Whitehouse of Rhode Island, says it would make little sense for the Obama administration to give the green light to Keystone after announcing tough new measures to reduce greenhouse gas emissions and a renewed commitment to developing cleaner sources of energy.
"If they're serious about carbon, and then they let Keystone go, it's pretty hard to figure out what's going on because the two are so in conflict," he told the program Platts Energy Week over the weekend.
Environmentalists point out that the ongoing Keystone XL review process likely explains Obama's reluctance to weigh in during Tuesday's speech.
"It's not a great surprise — we never expected that the president would come out right now and talk about Keystone," said Daniel Kessler of 350.org on Monday. "However, we think this means that he's more likely to turn down the pipeline."
That's because Obama is a "logical man," Kessler added.
"It doesn't make much sense to move forward on these other important pieces of his climate agenda, and then take a big step backwards with Keystone."
Susan Casey-Lefkowitz of the Natural Resources Defense Council said she agrees.
"Tea leaves cannot be read in the absence of the president delving into Keystone in this speech," she said.
"But he is attempting to launch an era of a new commitment to fighting climate change in the U.S., and in the wake of that, heading into the fall and winter, we believe that will mean a rejection of Keystone XL."
There's also speculation, however, that Obama may point to the initiatives he's announcing on Tuesday as cover if he opts to approve the pipeline later this year.
Keystone XL has become a flashpoint for U.S. environmentalists, who have branded it a symbol of "dirty oil" and have spent the past two years mounting a fierce public relations battle against the project.
At the same time, Calgary-based TransCanada has been pouring money into lobbying efforts in the U.S. capital. The company's CEO, Russ Girling, said recently that he's confident it will ultimately win approval.
Kessler said Monday he doesn't believe Obama will play politics with the pipeline in his second term.
"This isn't about politics, it's about the future of our planet," he said.
"We're already experiencing extreme weather — Calgary is under water right now. And this is about national security, this is an imperative to deal with, and Keystone is a big part of that — limiting the speed and size of the development of the tarsands if we're going to get climate change under control."
Obama rejected the pipeline in early 2012, but invited TransCanada to file a new application with an altered route that would skirt Nebraska’s ecologically sensitive Sand Hills region.
TransCanada did so, earning the thumb's up from the state of Nebraska. A draft assessment from the State Department suggested it posed minimal environmental risks and wouldn't lead to an increase in oilsands production.
The EPA, however, has said that State officials mistakenly concluded that oilsands bitumen would find buyers with or without the pipeline.
The State Department is now reviewing all the public comments on its draft environmental assessment, including the input from the EPA, before finalizing its draft report. Ninety days later, State officials will then determine whether Keystone XL is in the national interest of the United States.
After that, it will be up to Obama to determine Keystone XL's fate.