WASHINGTON  —  President-elect Donald Trump made hundreds of promises during his campaign, including dozens he vowed to implement on “Day One” of his administration. At the top of the list: closing the U.S. border with Mexico, mass deportations, increased oil and gas production, and retribution against his political opponents.

Many of his proposals would hit California hard, and Gov. Gavin Newsom has already promised to wage war in the courts against the new administration.

There’s plenty on Trump’s wish list to worry about. But as I wrote when he was elected to his first term, you can’t hit all your panic buttons at the same time.

Here’s an attempt to sort the biggest concerns from lesser ones. Which Trump priorities are worth losing sleep over — and which will be hard for him to carry out?

His top priorities, some with complications

Deporting undocumented immigrants

“Closing the border” has been Trump’s shorthand for a draconian crackdown on illegal immigration. He has repeatedly promised to launch “the biggest domestic deportation campaign in American history.”

A drive to expel every undocumented immigrant would deprive California of more than 7% of its workforce, potentially cripple agriculture and construction, divide families and disrupt communities.

It would also face a practical problem: The federal government doesn’t have enough immigration agents to round up 11 million people.

This is one promise Trump clearly intends to keep. But there may be a debate in the new administration over how fast and how sweeping the deportation drive should be.

“It’s not going to be a mass sweep of neighborhoods. It’s not going to be building concentration camps,” Tom Homan, a former acting director of ICE under Trump, said last month on CBS’ “60 Minutes.”

Polls show that most Americans want tougher enforcement of immigration laws — but they don’t support indiscriminate deportations, especially if they divide families. That’s how Trump’s first-term crackdown turned into a political disaster, forcing him to retreat.

Environmental rollback

Trump has the plans and the power to roll back some environmental gains. On Day One, he is expected to open more federal lands and offshore waters to oil and gas drilling. He is also likely to ease restrictions on the oil industry’s emissions of methane, a potent greenhouse gas, and to revoke Biden’s pause on increasing liquid petroleum gas exports.

Trump also plans to roll back Biden’s efforts to encourage the adoption of electric vehicles and repeal federal subsidies for solar, wind and other renewable energy projects — important parts of California’s drive to wean itself from fossil fuels. But a full-scale repeal of Biden’s 2022 energy law could run into resistance from Republicans in Congress, because much of the program’s spending has flowed into GOP districts.

The new administration is also likely to slow permits for new offshore wind energy projects. Trump has been a vociferous opponent of wind energy ever since Scotland built a wind farm that spoiled the view from one of his golf resorts.

Tariffs

“To me, the most beautiful word in the dictionary is tariff,” the president-elect said last month. He has proposed tariffs of at least 10% on goods from every other country and at least 60% on China — and as high as 200% on Mexico.

A president has wide authority to impose tariffs, and Trump has been so voluble about his love for the trade barriers that they appear inevitable. But tariffs — which are essentially taxes on imports — come with two problems. They raise prices on many of the goods Americans buy, pushing inflation upward, and they almost always prompt other countries to retaliate by imposing tariffs on U.S. exports.

Amid Trump’s first-term trade war with China, Beijing aimed retaliatory tariffs at California farmers; economists calculated that California growers of almonds, the state’s most valuable export crop, lost about $875 million.

Retribution

Trump has threatened to order the Justice Department to prosecute a long list of his political opponents, including Vice President Kamala Harris, Sen.-elect Adam B. Schiff and former U.S. Rep. Liz Cheney.

That’s not a new impulse on his part. During his first term, he publicly demanded that Atty. Gen. William Barr arrest Biden, former President Obama and former Secretary of State Hillary Clinton for what he claimed was a “treasonous plot” to spy on his 2016 campaign. (Barr ignored the order.)

If Trump appoints a more pliant attorney general this time, he has the power to order the Justice Department to investigate his critics, a GOP lawyer who is reportedly advising the president-elect wrote last week. The department’s independence from political meddling is a long-standing norm, but it isn’t protected by law.

Still, if he targets his critics, his term will be dominated by legal firestorms — potentially getting in the way of the rest of his agenda. Last month, he claimed that he refrained from prosecuting Clinton during his first term because “it would look terrible” — an implicit bow to political constraints.

Two actions Trump is virtually certain to take: He will order the Justice Department to drop the federal criminal proceedings against him, stemming from his attempt to overturn Biden’s election and his concealment of national security documents at his Florida estate. He has also promised to pardon most of the more than 1,000 people convicted of or indicted on charges of storming the Capitol on Jan. 6, 2021.

Yes, he can

Foreign policy

A president’s power to change direction in foreign policy is almost unfettered, and Trump has vowed to do exactly that. He has promised to negotiate an end to Russia’s invasion of Ukraine even before his inauguration — and his other statements suggest he would do so by demanding that Ukraine surrender chunks of its territory. (His running mate, Vice President-elect JD Vance, has called for an immediate end to military aid for Ukraine.)

Trump is also likely to renew his first-term drive to pull the United States out of the 75-year-old North Atlantic Treaty Organization, or at least to weaken the U.S. commitment to defend European countries against a Russian invasion.

Installing loyalists

Trump has promised to impose new rules on the federal civil service allowing him to fire bureaucrats more easily and replace them with loyalists. He imposed such a rule in the final months of his first term, but Biden revoked it.

He has also promised to fire senior military officers whose political views he dislikes and to purge the CIA and the FBI, accusing both agencies of “persecuting” conservatives.

Those moves “would turn much of the civil service into an army of suck-ups,” Robert Shea, a former aide to President George W. Bush, told me this year.

Trump vs. political reality

Abortion

One issue on which Trump may hesitate to buck public opinion: Abortion. Polls show that most voters oppose harsher restrictions, and last week, voters in seven states — including conservative Missouri and Montana — approved abortion rights measures.

During the Republican primaries this year, Trump sought to take credit for nominating the conservative Supreme Court justices who enabled states to pass restrictive abortion laws. But once he was running in a general election campaign, he sought to avoid responsibility for the laws, arguing that he had left the question up to the states.

Some antiabortion activists want Congress to pass a national abortion ban, but Trump said during the campaign that he would not sign one into law. Trump has also indicated he does not intend to block access to mifepristone, the pill used for more than half of U.S. abortions. “The matter is settled,” his spokeswoman, Karoline Leavitt, said last month.

Activists expect the Trump administration to revoke a Biden directive that requires emergency rooms to provide abortions when necessary to stabilize a woman’s health, even in states with abortion bans.

Obamacare

Conservative Republicans in Congress, including House Speaker Mike Johnson (R-La.), have said they hope to repeal or weaken the Affordable Care Act, the health insurance law popularly known as Obamacare.

Trump has said he is open to changing the popular law, which he tried and failed to repeal in his first term. But he has not presented a proposal, and admitted in the debate that he had only “concepts of a plan.”

If the new Congress fails to renew Biden-era subsidies, as many as 20 million users — especially middle and high income families — will see their health insurance costs rise.

Not likely to happen

Some of Trump’s promises aren’t likely to survive the real world.

He pledged to exempt Social Security benefits, overtime wages and tips from taxation. Many Republicans in Congress say privately that those ideas are impractical, because they would cost trillions in lost revenue.

Trump also promised that his pro-oil policies would cut energy prices by 50%. But energy prices are set by a global market; even if Trump stimulates a massive increase in oil production (which isn’t a sure thing), the effect on prices may not be dramatic.

Trump has also threatened to cancel television networks’ broadcast licenses. But the federal government grants licenses to individual stations, not networks — and it cannot cancel licenses because a president doesn’t like their news coverage.

Where are the restraints?

Trump, like all presidents, will hold vast power. But even a strongman may discover that there are limits to what he can do.

Courts can still overturn an administration’s actions — and Democrats, including California’s governor, are preparing to spend much of the next four years going to court.

The most important factor could be public opinion. Trump may have waged his last campaign, but Republicans in Congress face another election in two years. They know that voters often punish the party in power, especially if they believe the president has gone too far.

So the 2026 congressional election may be the strongest restraint on what Trump can do — and that campaign is already underway.