President-elect Trump is expected to get to work immediately upon taking office enacting major changes on immigration, energy and foreign policy.

Trump late last year suggested he would not rule as a dictator “except for day one,” a sign he intends to use executive authority aggressively to implement changes to immigration policy and energy policy in particular.

Trump has also signaled he would move swiftly to roll back protections for transgender youth, and he would fire the man prosecuting a criminal case against him.

Here’s a look at what Trump has said he will do “on day one.”

Immigration

Much of Trump’s day one agenda is likely to be focused on cracking down on immigration.

“All of the secure border policies that we had in place with President Trump, he can simply flip the switch and put those back in place just like they were before. They didn't need an act of Congress,” senior campaign adviser Jason Miller said Wednesday on NBC's "Today."

At nearly every campaign rally this cycle, the former president’s prepared remarks included the line: “On day one, I will launch the largest deportation program in American history.”

Carrying out such a massive deportation operation, which Trump has said will target those in the country illegally and particularly those with criminal records, will be a massive logistical lift. He has said he will rely on local police departments for assistance, but the effort will require extensive coordination with federal agencies and would likely face resistance from some local jurisdictions.

It will also be expensive. The American Immigration Council released an October study that found a mass deportation effort aimed at removing 13 million immigrants in the country illegally would cost at least $315 billion.

Other actions Trump may take immediately would likely rely on executive authority. Trump has vowed to sign an executive order “on day one” to stop federal agencies from giving automatic U.S. citizenship to the children of illegal aliens. An effort to end birthright citizenship would face certain legal challenges.

The president-elect would also likely resume construction of a wall along the southern border, something the Biden administration halted, and Trump could also look to reimpose policies like the “Remain in Mexico” program, which forced potential asylum-seekers to stay in Mexico to wait out the results of their cases in U.S. immigration court.

Energy and climate measures

Trump has pledged on day one to “drill, baby, drill,” a vague campaign slogan that signals he will seek to further ramp up oil production from already record-setting levels. He has also outlined more specific steps he will take to reverse Biden-era environmental regulations.

On his campaign website, Trump included a pledge to “roll back every Biden policy that is brutalizing American autoworkers” on day one. Trump has repeatedly signaled he would seek to roll back regulations requiring automakers to meet certain emissions standards that incentivize increased electric vehicle production.

Trump in August said he would eliminate a Biden administration rule cracking down on planet-warming emissions and other pollution from power plants. During his time in the White House, Trump issued significantly less stringent rules for power plants. 

At a New Jersey rally earlier this year, Trump told the crowd he would sign an executive order on “day one” to halt windmill projects, targeting a key source of clean energy.

Trump could also move to withdraw from the Paris Climate Accords once again, taking the U.S. out of the global pact to lower emissions. Trump pulled out of the accords during his first term, but President Biden rejoined the agreement after he took office.

Foreign policy

Trump has vowed on day one to return “to a foreign policy that puts America's interests first,” a sharp reversal from the Biden administration, which emphasized international alliances and led support for Ukraine in its war against Russia.

He has claimed he would end the war between Russia and Ukraine before even taking office, though he has not provided specifics on how he would do so. Trump’s comments have caused alarm among Ukraine’s allies that he will call for a peace deal that allows Russia to claim Ukrainian territory it has invaded.

Trump has similarly sparked concerns about his commitment to NATO. ​​Congress last year approved legislation that would prevent any president from withdrawing the United States from the alliance without approval from the Senate or an act of Congress. 

The former president has also mused that he would not protect a NATO ally from an attack if they had not contributed an adequate amount to defense spending.

Reversing Biden orders on equity

One of Trump’s biggest applause lines at rallies has consistently been when he vows to keep men out of women’s sports and end “transgender insanity,” and he has already laid out how he will roll back protections for transgender youth.

Trump has said that on day one, he will revoke transgender student protections enacted earlier this year by the Biden administration. The Education Department in April unveiled a final set of changes to Title IX to cover discrimination based on sexual orientation and gender identity for the first time. The Supreme Court in August sided with 10 GOP-led states that had sued to prevent the enforcement of the new rules.

The former president has also said he would move on day one to revoke a Biden executive order to “embed equity principles, policies, and approaches across the Federal Government.” Trump has said he would reinstate a 2020 order of his own banning the promotion of concepts that the U.S. is fundamentally racist or sexist or that one race or sex is inherently superior.

The former president has also threatened to cut off federal funding for schools that promote vaccine mandates. The threat emerged amid clashes over COVID-19 vaccine and mask requirements, but it has alarmed public health experts who worry it would apply to other vaccines like measles.

Firing Jack Smith and pardoning Jan. 6 offenders

Trump has signaled he will move almost immediately after taking office to fire special counsel Jack Smith, who is overseeing the federal case against Trump in Washington, D.C., over his efforts to subvert the 2020 election and remain in power.

“I would fire him within two seconds,” Trump said in late October.

The president-elect has also repeatedly pledged to pardon individuals convicted of crimes for their actions on Jan. 6, 2021, when his supporters violently stormed the Capitol to stop the certification of election results.

"The moment we win, we will rapidly review the cases of every political prisoner unjustly victimized by the Harris regime. And I will sign their pardons on day one," Trump said at a September rally.

The former president has also signaled he would look to go after Democratic prosecutors in response to the legal cases brought against him in recent years over his handling of classified documents, his efforts to overturn the 2020 election results and his business practices.

“In Chicago, San Francisco, Los Angeles, and every other city where these maniacs have taken over, the DA’s offices should face federal subpoenas of their staff, their emails, and their records to determine whether they have blatantly violated federal civil rights law,” Trump said in a video posted by his campaign in April 2023.