Day One could be a dud for those Americans hoping Donald Trump will undo the Obama years in a single swoop.
While the president-elect is poised to take swift action on immigration, guns and business, the slow-moving federal system will make it difficult for Trump to fulfill many of the lofty expectations he has set for the first 100 days — much less for Jan. 20, his inaugural day in office.
Nowhere is that reality starker than in the realm of environmental regulations.
President Barack Obama pushed an aggressive climate agenda, sending shockwaves through the energy industry. Some of his advances have been baked in by bureaucracy and the passage of time. And many environmental groups stand ready to defend that legacy.
A quick reboot simply isn't an option.
"Even with a united government in 2017, it will be an uphill climb to roll back the damage done by this administration," said Rep. Lamar Smith, a Texas Republican who chairs the House Science, Space and Technology Committee.
Given Trump's rhetoric and a Cabinet set to be stocked with energy insiders, there's little doubt about the next administration's ultimate direction. But the reality is that the Republican's reshaping of Obama's environmental work will more likely be measured in months or years.
Trump could move quickly, for instance, to ease the way for the contentious Dakota Access pipeline. But other measures, such as the Clean Power Plan, are tied up in court. Still others, like a mercury pollution rule, would have to be unwound through laborious rule-making processes.
"There are certainly executive actions that he can take on Day One," said Susan Dudley, a top regulatory official under George W. Bush. "But when it comes to regulations, to accomplish things in the first 100 days, he will really need to rely on other branches of government."
That sort of calculation will play out across Trump's administration, as the billionaire looks in all fields to make good on his pledge to "drain the swamp."
Congress will provide the path forward for Trump on some of his big-ticket items, such as repealing Obamacare or peeling back high-profile banking regulations. And the billionaire has already shown his desire to cut deals, whether it's over tax incentives or trade agreements.
But climate policy offers the full scope of the battlefield, one complicated by the president-elect's own views.
He's met of late with noted climate activist Al Gore. But he's called climate change a "hoax." He's walked back his toughest talk on withdrawing from a global climate accord. But he's vowed to "cancel the restrictions on the production of American energy."
Though Trump has said he's "very open-minded" about the environment, his pick to run the Environmental Protection Agency is a climate change skeptic who's fought the federal government on related issues.
Still, an energy summit hosted recently in Washington by two conservative groups, the Heritage Foundation and the Texas Public Policy Foundation, offered a sense of expectations. What could've been a funereal exercise if Hillary Clinton had won was instead a celebration.
"The big thing that has changed is that there is hope," said Brooke Rollins, the policy foundation's president.
Among those in attendance was Kathleen Hartnett White, a policy foundation adviser whom Trump considered for EPA administrator.
She said the Texas energy industry — and the state's economy — stands to benefit from a White House that doesn't pursue Obama's "aggressive regulatory initiative." But she also cautioned against expecting "slash-and-burn reviews" or a president who is just "gutting regulations."
That's even if the end result takes a bit longer.
"It's very much a 'both, and' situation," she said. "Quick actions which are legally possible and then the beginning of what are far longer processes to reform EPA."
The low-hanging fruit for Trump will be any executive orders _ such as a moratorium on coal leasing from federal lands. He could also put a hard stop on any rule not yet finalized. And he could start laying the foundation to pare back agency budgets set aside for enforcement.
But to undo fully vetted regulations, Trump's administration would have to go through the same monthslong rule-making process.
That could mean a time-consuming lift to roll back rules on mercury pollution or methane standards for oil and gas drilling. It would be even harder, experts said, to unravel the EPA's critical findings on the public health dangers of carbon dioxide and other greenhouse gases.
"That would be a very hard mountain to climb, given the voluminous scientific record behind the endangerment finding," said Jody Freeman, an expert on environmental regulations at Harvard Law School.
One other option for Republicans would be to invoke a little-used law that allows Congress to overturn agency rules finalized in the preceding 60 legislative days.
But there are only a select number of such rules, such as a stream buffer regulation that affects coal mining. And given Republicans' other higher-profile priorities, lawmakers might decide instead to leave fights over some regulations to other government branches.
"It's just hard to pick what of the parade of horribles we will see early," said Lisa Gilbert, director of the Congress Watch division at Public Citizen, a staunch advocate for environmental regulation.
Trump's biggest climate battles might depend on the courts.
The president-elect, for instance, has made clear his dislike of the Clean Power Plan, Obama's effort to reduce power plants' carbon dioxide emissions. The fate of the plan — challenged by Texas and a host of other states — will almost certainly be decided by the Supreme Court.
Depending on the next steps, Trump's Department of Justice could choose to effectively back off the case. But then interveners _ such as the states supporting the plan — could fill that void, furthering complicating the legal quagmire, experts said.
Taking in all those variables, at least one environmental leader in Texas remains upbeat. Though John Hall of the Environmental Defense Fund said it's "not the best of times" for his side of the issue, he pointed out that market forces are already driving a push toward clean energy.
"While the Trump administration may be able to repeal the Clean Power Plan and may be able to slow things down, we don't believe the new administration can reverse what's happening in Texas," he said, referring to the state's extensive wind and natural gas energy production.