President Donald Trump faces an arduous task delivering on his Inauguration Day promise of a “Golden Age of America” in the face of a closely split Congress, inevitable lawsuits and recalcitrant world leaders.

After taking the oath of office, Trump outlined a series of sweeping executive orders, the first steps in enacting a far-reaching agenda to expand America’s territory, curb immigration, boost fossil fuel production and roll back environmental regulations.

Trump’s allies and advisers have been drafting executive orders and agency regulations for months. They argue privately and publicly they are better prepared to enact their vision than they were during Trump’s 2017-2021 term, when Republican infighting and a lack of foresight led to setbacks in the courts and in Congress.

Trump will benefit this time from a deeply conservative Supreme Court, which handed him some major legal victories on the campaign trail. A third of its nine members are his appointees.

But having already served one term, he will leave office in four years, and many of his proposals are so norm-shattering they are certain to result in extensive litigation that tests the boundaries of constitutional law.

Advocacy groups - from the environmental activist group the Sierra Club to the American Civil Liberties Union - are putting together plans to push back.

Representatives for Trump did not respond to a request for comment.

IMMIGRATION

No policy area will be subject to more aggressive pushback from Democrats and civil rights organizations than immigration.

Trump’s team confirmed on Monday it plans to try to end birthright citizenship, a long-held constitutional principle that holds the vast majority of people born in the United States are automatically citizens.

Individuals denied citizenship benefits will sue, legal experts say, leading to a protracted legal dispute. Most scholars believe birthright citizenship is enshrined in the US Constitution’s 14th Amendment, and they say the Constitution gives Congress the power to regulate citizenship.

No president before Trump has attempted to redefine citizenship rules through executive action.

Another element of Trump’s promised immigration plan - invoking the Alien Enemies Act of 1798 - would also face legal pushback. The seldom-used act generally allows for the deportation of certain foreigners during times of conflict. It has only been used three times.

George Fishman, a former Homeland Security official under Trump, told Reuters last year that the Trump administration would need to prove the immigrants were sent by a foreign government.

“I worry a little about overpromising,” Fishman said.

Trump also said in his inaugural address that his administration would deport “millions and millions of criminal aliens” but a deportation effort of that scale could cost tens of billions of dollars and would likely last years.

TIKTOK ON THE CLOCK

One of Trump’s most tenuous promises could be keeping TikTok online in the United States.

While Trump did not bring up the social media app during his inaugural address on Monday, he has recently signaled he would keep the app functioning. It was essentially banned starting on Sunday, but apart from a brief interruption for US users, it remained online after Trump said he would try to save it.

All the same, Trump’s long-term options may be limited.

Biden could have granted TikTok’s owner, Bytedance, an additional 90 days to find a US buyer if certain terms were met, said Colin Costello, an attorney with Freshfields and a former intelligence official. But Biden did not grant that extension and, now that the deadline has expired, the extension option may be off the table.

Halting the ban on a longer-term basis, Costello said, could require Trump to direct the Justice Department to “deprioritize” or not enforce the law, probably for a specified period of time. That would result in legal uncertainty, however, that tech companies might not be willing to assume.

Trump’s legislative options may be limited, too. Some allies in the US Senate and House of Representatives have publicly bucked Trump, saying TikTok needs to be sold to a US company or cease operating immediately.

UKRAINE, PANAMA, MARS

Trump pledged frequently during the 2024 election campaign to solve the Ukraine war before even taking office. But he missed that deadline, and his advisers now concede it will take months to reach a peace deal.

During his inaugural address, Trump also repeated his aspiration to take back the Panama Canal, though it is the sovereign territory of an ally, and it is unclear how he would do so.

The president said he would rename the Gulf of Mexico the “Gulf of America.” While he can direct the US Geological Survey to make such a change, it would be unlikely to be recognised internationally.

He also vowed that the United States would send a man to Mars during his term, which will end in January 2029. He has his work cut out for him. The moon, for reference, is about 239,000 miles from Earth while Mars is, on average, about 140 million miles away.

The US space agency NASA in December announced new delays in sending US astronauts back to the moon.

‘DRILL, BABY, DRILL’

Trump said on Monday he would declare a national energy emergency to unleash domestic fossil fuel production. While legal experts say presidents have broad authority to declare national emergencies, Biden has put up some roadblocks to specific measures that Trump may want to take.

For instance, Biden earlier this month used the Outer Continental Shelf Land Act to ban oil and gas drilling in all federal waters off the East and West coasts, the eastern Gulf of Mexico and portions of the Bering Sea in Alaska. Trump has said he would revoke that ban, but legal experts say it is unclear that presidents have that authority.

During Trump’s first term, he tried to undo a federal ban on drilling near Alaska via an executive order, but a federal judge determined his order was unlawful.

Federal law gives Trump the ability to declare an energy emergency, which may allow him to temporarily suspend emissions rules for power plants and skirt environmental review for energy projects.