BUENOS AIRES, Argentina (AP) — Donald Trump, the disruptive, anti-establishment president who spent years deriding much of what George H.W. Bush stood for, set aside differences in politics and temperament Saturday to honor the late president.

Trump declared a day 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, who was president from 1989 to 1993,...