Donald Trump and his Republican Party have an ambitious agenda and control of the US Congress.

Trump has said he will "make heads spin" as he moves full-speed ahead after his inauguration on 20 January.

His team has said to expect a flurry of executive orders - directives from the US president - out of the Oval Office in the first week.

Policy experts and lawyers are already drafting those orders as part of the administration's transition.

Still, advocacy groups and Democratic state governors have vowed to challenge at least some of those plans.

Here is what the president-elect has said about his second-term priorities.

Immigration and the border

Trump press secretary Karoline Leavitt told Fox News on Sunday "We know he promised to sign an executive order to secure the southern border".

"We know that on day one he is going to launch the largest mass deportation of illegal immigrants in American history," she said.

In the week since his re-election, Trump has prioritised filling leadership positions that would oversee immigration, suggesting he is preparing to tackle his plans for border policy early.

He tapped veteran immigration official Tom Homan as his "border tsar"; selected South Dakota Governor Kristi Noem to oversee homeland security; and appointed Steven Miller as White House deputy chief of staff for policy. Mr Miller is best known for shaping some of Trump's most restrictive policies on illegal immigration during his first term.

Any mass deportation programme could face logistical difficulties as well as a flurry of legal challenges from immigration and human rights activists.

Trump could also re-implement his "Remain in Mexico" policy that required asylum seekers to wait in Mexico while claims are processed.

President Joe Biden had called the programme "inhumane" and tried to end it on his first day in office, but faced legal challenges. In 2022, the Supreme Court allowed him to move ahead.

During the Trump administration, about 70,000 asylum seekers were returned to Mexico to wait for their hearings.

Another day one promise was to end birthright citizenship - the 150-year-old principle that says anyone born on US soil is an American citizen.

It's not clear how Trump plans to achieve this policy. He has pledged an executive order but birthright citizenship is explicitly guaranteed by the US Constitution, meaning it can only be altered under specific circumstances.

He would need states to agree to a national convention or a two-thirds vote in favour in the narrowly split Congress to propose a change, then subsequent approval by three-fourths of state legislatures - of which Republicans control just over half.

6 January

Trump did not mention pardons in his victory speech, but he has long suggested that pardoning those convicted of storming the Capitol in 2021 would be a priority.

"Oh, absolutely, I would. If they're innocent, I would pardon them," Trump said during a panel at the National Association of Black Journalists.

US presidents have wide authority to forgive people convicted of federal crimes or end their prison sentences. Prosecutors may also decide to drop pending cases depending on who Trump might choose to pardon.

What's less clear is who might get a pardon.

At one point, Trump told CNN: "I am inclined to pardon many of them. I can't say for every single one, because a couple of them, probably they got out of control."

Ms Leavitt told the Washington Post that he will decide “on a case-by-case basis when he is back in the White House”.

More than 1,500 people were arrested in connection with the Capitol riot. According to federal numbers, more than 750 of them were sentenced for crimes ranging from trespassing to assaulting police officers and seditious conspiracy.

Jack Smith

Trump has also faced his own legal challenges over his actions following the 2020 election and a separate classified documents case.

Special Counsel Jack Smith, a veteran prosecutor appointed to oversee the US Department of Justice's investigations into Trump, filed charges, to which the president-elect has pleaded not guilty.

This week, sources told CBS News that Mr Smith plans to resign before Trump takes office and avoid Trump's promises to fire him. The BBC's US media partner also reported that his office would wind down the two cases it was pursuing against Trump.

It remains unclear whether Trump and his supporters will still try to punish Mr Smith. Congressional Republicans have reportedly implied they intend to investigate his work.

"Jack Smith’s abuse of the justice system cannot go unpunished", billionaire and Trump ally Elon Musk posted on social media.

Trump had said firing Jack Smith is one of his top priorities.

"I would fire him within two seconds. He’ll be one of the first things addressed," he said in an interview in October.

Trump regularly railed against the special counsel in interviews and online, calling him a "crooked person", a "scoundrel" and other insults.

Smith's cases were already facing an uncertain future. The Supreme Court ruled in July that presidents have partial immunity from criminal prosecution for their conduct in office, undermining Mr Smith's work.

Trump's electoral win also gives him the power to pardon himself of any federal crimes, though no president has done so before.

Paris climate agreement

In his 2016 campaign, Trump made withdrawing from the Paris climate agreement a priority. Within six months of taking office, the United States moved to exit the landmark deal.

President Joe Biden made rejoining the agreement one of his top priorities when he ran against Trump in 2020. Biden signed a letter requesting the US be readmitted on his first day in office.

How will Trump respond in his second term? Media reports suggest that his team is preparing orders to withdraw once again when he takes office in January.

Leaving the agreement would mean the US is no longer beholden to meeting set carbon emissions reductions.

Among other priorities at odds with the Paris standards, Trump has said he wants to prioritise US production of oil and gas. He promised to quickly expedite permitting and fracking - "We’re drilling, drilling, drilling," he told Fox News host Sean Hannity last year.

Trump has also criticised the Biden administration's plans to expand wind energy and increase electric car production, which could be early targets in his new administration.

Russia and Ukraine

On the campaign trail, Trump said he could end the war in Ukraine "in a day". He has also repeatedly criticised the US government's continued support of Ukraine, casting the war as a drain on resources.

He has not yet given specifics on how he would negotiate the war's end beyond saying he would help the two countries strike a deal.

Since his re-election, Trump has spoken to Ukrainian President Volodymyr Zelensky in a call that lasted "about half an hour", with billionaire Elon Musk also taking part. A source told the BBC that "it was not really a conversation to talk about very substantial things".

The Kremlin denied that Trump held a call with Vladimir Putin, though media reports said Trump warned the Russian president against escalating the war in Ukraine.

Trade and economy

The economy is an issue that Trump heavily campaigned on, vowing to end inflation as soon as he takes office.

“We will target everything from car affordability to housing affordability to insurance costs to supply chain issues,” Trump has said.

“I will instruct my cabinet that I expect results within the first 100 days, or much sooner than that.”

He said he would sign an executive order that directs every cabinet secretary and agency head to “use every tool and authority at their disposal” to defeat inflation and to bring consumer prices down.

Trump’s plan includes imposing tariffs on imported goods, especially those coming in from China, arguing that these taxes would keep manufacturing jobs in the US.

It’s still unclear how widespread these tariffs will be, but Trump has raised the prospect of at least a 10% across-the-board tariff on imported goods, as well as a 60% import tax on goods from China.

He also vowed to target Mexico with his tariffs.

“I’m going to inform (the Mexican president) on Day 1 or sooner that if they don’t stop this onslaught of criminals and drugs coming into our country, I’m going to immediately impose a 25% tariff on everything they send into the US,” he has said.

These tariffs would probably not need congressional approval.

Trump already introduced tariffs in his first term, citing Section 232 of the Trade Expansion Act of 1962, which empowers a president to impose duties on goods that could affect US national security.

Another promise is to “end the Biden-Harris war on American energy”, Trump has said, vowing to ramp up oil drilling and fracking as a way to lower the cost of energy bills for consumers.

Trump can do this with an executive order that rolls back environmental protections, which would allow him to halt clean energy projects and scrap climate targets set by the Biden administration.

The president-elect has also vowed to fire Gary Gensler, the chairman of the Securities and Exchange Commission, on day one. Gensler, who was appointed by Biden, pushed for climate disclosure rules and strong enforcement of the cryptocurrency market.

Trump has championed cryptocurrency, and his election saw the value of Bitcoin go up by 30% in the past week due to an expectation that his administration will be more crypto-friendly.

Title X

Donald Trump has vowed to undo the changes made by President Biden to Title X, the country’s only national, federally-funded family planning programme.

In 2019, during his first term, Trump’s administration implemented a new rule that prohibited any health provider in the Title X network from mentioning abortion to patients, even if a patient raised questions about it themselves.

The change effectively stripped tens of millions of dollars from organisations such as Planned Parenthood that offer or refer patients for abortions.

But just months later, when Biden took office, he had that policy reversed.

Now, it’s expected that Trump will change the rules again.