BUENOS AIRES — President Trump, who spent years deriding much of what George H.W. Bush stood for, set aside differences in politics and temperament Saturday to honor the former president a day after his death.

Trump declared a period of national mourning and ordered American flags to be flown at half staff for 30 days to honor a man of ‘‘sound judgment, common sense, and unflappable leadership.’’ The president and first lady Melania Trump added that Bush had ‘‘inspired generations of his fellow Americans to public service.’’

Bush, 94, died shortly after 10 p.m. Friday at his home in Houston, according to a statement from a family spokesman. The longest-living president in American history, he used a wheelchair in recent years after being diagnosed with a form of Parkinson’s disease. His wife of 73 years, Barbara, died on April 17 at age 92.

His last words, according to The New York Times, came when his son, former president George W. Bush, offered his final thanks to his father via a speaker phone as friends and members of his family were at the senior Bush’s side.

“I love you, too,’’ George H.W. Bush said to his son.

“George H.W. Bush was a man of the highest character and the best dad a son or daughter could ask for,’’ George W. Bush later said in a statement.

Bush had struggled for days, not getting out of bed, eating almost nothing, seemingly in decline from Parkinson’s. But when the end came, said James A. Baker III, Bush’s friend and confidant of 40 years, ‘‘it was a very gentle and peaceful and easy passing.’’

Baker and his wife, Susan, were there at the end, the third visit of the day for the former secretary of state. The first visit had come Friday morning. Baker had risen early and gone to see Bush, who lived not far away.

He arrived about 7:15 a.m. and found Bush sitting up in bed. One of Bush’s caregivers told the former president that ‘‘Secretary Baker is here.’’

‘‘He looked up at me and said, ‘Bake, where are we going?’ ’’ Baker said in a telephone interview. ‘‘I said, ‘Jefe, we’re going to heaven,’ and he said, ‘That’s where I want to go.’ ’’

Bush had always been Mr. President to Baker when Bush was in the White House and Baker was his secretary of state. But once Bush was out of office, Baker said he always called him ‘‘Jefe,’’ Spanish for ‘‘chief.’’

He and Baker had gone out for oysters on the half shell two weeks ago. “Then things sort of went downhill from there,’’ Baker said.

The White House announced that the Trumps would attend a state funeral for the former president at Washington’s National Cathedral.

The announcement marked a reversal from earlier this year, when the president was pointedly not invited to the funeral of Barbara Bush. Melania Trump attended instead.

The quarter-century since Bush left office featured his Republican Party’s steady march away from his steely pragmatism and international partnership, culminating in the dramatic break from long-held GOP principles ushered in by Trump’s election.

While Trump spoke graciously Saturday, he has not always been so kind to Bush or his family. He ran against one of Bush’s sons, Jeb Bush, in the GOP presidential primaries in 2016, and was sharply critical of the two-term presidency of George W. Bush.

Trump said he spoke with George W. Bush and Jeb Bush to express his sympathies.

Trump announced that he has authorized the use of the Boeing 747 presidential aircraft, known as Air Force One whenever a president is on board, to transport Bush’s remains to Washington — a customary honor for a former president. Bush is to lie in state in the Capitol Rotunda from Monday evening through Wednesday morning.

Trump also closed government offices Wednesday and designated it as a national day of mourning, which traditionally occurs on the same day as the Washington component of a late president’s state funeral.

US financial markets will close Wednesday.

Trump’s proclamation hails Bush as ‘‘one of America’s greatest points of light,’’ a reference to one of his signature phrases about the impact of American civic culture.

Trump mocked the phrase at some of his campaign rallies this year. He contrasted it with his own slogan, saying ‘‘Putting America first, we understand. Thousand points of light, I never quite got that one.’’

Those harsh assessments were set aside in the Trumps’ comments Saturday.

‘‘President Bush guided our nation and the world to a peaceful and victorious conclusion of the Cold War,’’ the Trumps wrote. ‘‘As President, he set the stage for the decades of prosperity that have followed.’’

Material from The Washington Post, The New York Times, and Bloomberg News was used in this report.