Why does Donald Trump keep calling President Biden 'Obama' on the campaign trail?

WASHINGTON − Former President Donald Trump has repeatedly referred to President Joe Biden as "Obama," most recently in a campaign speech Saturday.

"Putin, you know, has so little respect for Obama that he’s starting to throw around the nuclear word," Trump said at a rally in Virginia on Saturday. He later added, "We have a fool as a president."

Trump has confused Biden and former President Barack Obama at least seven times before in recent months, according to Forbes.

Trump seemingly made the same mistake on Fox News last month when telling Sean Hannity that Obama is "going to end up being indicted when he leaves office" if the Supreme Court doesn't endorse Trump's expansive view of presidential immunity.

A string of memory mistakes

The 77-year-old Republican frontrunner has made similar errors at rallies in New Hampshire and Iowa, during several Fox News interviews last fall and during a September speech in Washington, D.C.

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Trump has suffered other recent memory lapses, such as warning that "We would be in World War II very quickly if we’re going to be relying on [Biden]" and referring to Hungarian Prime Minister Viktor Orban as "the leader of Turkey."

The former president took to Truth Social in November to say he hasn't mixed up Biden and Obama's names and instead "sarcastically" replaces Obama's name for Biden.

"I know both names very well, never mix them up, and know that they are destroying our country," Trump wrote.

"Is that also his explanation for not knowing World War II happened? Or that Turkey's a different country than Hungary?" a Biden campaign advisor responded in part.

Two older candidates with a tendency to misspeak

Biden, 81, has had his own share of gaffes throughout the last year − tripping on stage, calling out to a congresswoman during a news conference a few weeks after she died in a car accident and mixing up names of world leaders.

The Justice Department's special counsel report, on Biden's handling of classified documents described him as a "well-meaning elderly man with a poor memory."

Republicans and Trump himself have used the report to attack Biden's mental acuity, claiming he isn't fit to serve a second term.

Biden has acknowledged his mishaps, referencing his stuffer and using humor when confronting his age, joking over the summer to a crowd of reproductive rights activists that he is 198 years old.