WASHINGTON —  President Trump has begun his second term pressing his power to reshape the government by firing federal officials, ending diversity policies and deporting immigrants who are in this country illegally.

Despite fierce criticism, he is likely to succeed on those fronts because the Constitution and the laws generally put those powers in the hands of the president.

“Under our Constitution, the executive power — all of it — is vested in a president,” Chief Justice John G. Roberts Jr. said in 2020. And that includes the president’s nearly “unrestricted removal power” of officials throughout the government, he said.

The court’s conservative majority has also struck down racial diversity policies in universities and said repeatedly that the president has broad authority to enforce immigration laws.

In some areas, however, Trump appears to be claiming powers that go well beyond the president’s authority set out in the Constitution.

He says he can, by executive order, rewrite the 14th Amendment of 1868 and deny citizenship to some children who are born in the United States to parents who are not citizens.

And this week, the White House claimed the power to temporarily freeze federal spending that has been approved by Congress to see whether it is aligned with “presidential priorities.”

On Wednesday, the White House quickly rescinded the freeze memo that set off alarm and confusion across the country. But a legal debate persisted over whether Trump exceeded his authority by making the move.

The Constitution gives Congress what is often called the “power of the purse.” While the president may propose a budget and veto spending bills he opposes, Congress in the end gets to decide how much is spent and for what.

The current spending measures came from the Republican-controlled House of Representatives. Even so, Trump’s Office of Management and Budget said in its two-page memo that it needed to pause spending to prevent using federal money to “advance Marxist equity, transgenderism and green new deal social engineering.”

Despite those novel claims, the conflicts over spending are not new.

Presidents have often disagreed with Congress on budget matters, and the dispute flared up in the early 1970s when President Nixon refused to spend money on social programs that had been supported by congressional Democrats.

In response, Congress adopted the Impoundment Control Act of 1974 to resolve disputes. It says the president may seek to “defer” some spending temporarily or “rescind” it entirely if Congress approves. This hold or pause can last for 45 days.

Under that law, the Trump administration could ask Congress to reconsider some spending items. But if Congress refuses, the law says the money must be disbursed.

Trump, however, has insisted the impoundment act is unconstitutional, and he has been determined to challenge it. His campaign website said the law’s restrictions infringe the president’s powers to “crush the Deep State.”

Moreover, he said, “leading constitutional scholars agree that impoundment is an inherent power of the president.”

Stanford Law professor Michael M. McConnell, a former federal appeals court judge appointed by President George W. Bush and the director of its constitutional law center, finds that claim questionable.

“I do not know a single scholar who thinks the president has the constitutional authority to violate the Impoundment Control Act,” McConnell said.

A federal judge in Seattle has temporarily blocked Trump’s order ending birthright citizenship and described it as “blatantly unconstitutional.”

On Tuesday — before Trump rescinded the spending-freeze memo — a federal judge in Washington, D.C., temporarily blocked the administration’s “pause” on federal spending.

White House Press Secretary Karoline Leavitt said rescinding the memo should “end any confusion.” But she added that the budget office will continue to examine the spending programs to see whether they comply with Trump’s executive orders.

These tests of presidential powers may ultimately reach the Supreme Court, particularly if Trump administration lawyers file emergency appeals to challenge any judges who block his orders.

They will go before a court with six conservative justices who are Republicans appointees — three named by Trump — and believers in strong executive power.

Last year, justices surprised many legal experts when they ruled broadly that an ex-president cannot be prosecuted for “official acts” while in the White House.

“Under our constitutional structure of separated powers,” the president may not be punished in court for the “exercise of his core constitutional powers,” Roberts wrote in Trump vs. U.S.

Now, the court may have to decide whether the president’s powers extend well beyond the core duties of his office.