Donald Trump launched another vicious attack Monday on his political opponents, choosing the Memorial Day holiday -- when the United States marks its fallen soldiers -- to dismiss his adversaries as "human scum."

As Americans honored their troops who have died in conflict with visits to cemeteries and backyard cookouts with family and friends, the Republican former president posted on his Truth Social platform against his perceived enemies.

These included judges who oversaw or are overseeing cases against him -- civil ones for sexual assault and business fraud, and the current, history-making criminal trial stemming from hush money payments to a porn star right before the 2016 election.

"Happy Memorial Day to All, including the Human Scum that is working so hard to destroy our Once Great Country," said Trump, who is leading in many swing state polls as he prepares to take on President Joe Biden in the November election.

He went on to attack his various legal adversaries, calling one of the judges "wacko." He also took a swipe at E. Jean Carroll, a former magazine columnist whom he was found liable in a civil case for sexually abusing in 1996 and defaming. A judge has ordered him to pay her $88 million.

In a separate post Trump did publish a picture of himself saluting at a grave covered with an American flag, and a caption reading "We can never replace them. We can never repay them. But we can always remember them."

His dismissal of people as "human scum" was in line with other comments in which Trump has derided some people as less than human.

He has called the US left "vermin" and said migrants crossing the border from Mexico "are poisoning the blood of our country." Both remarks have been criticized as evoking Nazi Germany.

Trump's fiery post Monday stood in contrast with emotive comments Biden made during his yearly holiday pilgrimage to Arlington National Cemetery, the vast burial ground of US soldiers across the Potomac River from Washington, with row after row of white headstones.

In a speech Biden noted that the cemetery held the remains of soldiers killed in every US war starting with the Civil War of the 1860s, through the World Wars in Europe and up to Iraq and Afghanistan in contemporary times.

"Today, we bear witness to the price they paid," Biden said.

"Every white stone across these hills, in every military cemetery and churchyard across America: a father, a mother, a son, a daughter, a brother, a sister, a spouse, a neighbor -- an American."