Trump has tried to rescind his "Crazy Nancy" (Pelosi) nickname – admitting it was a "copy of Crazy Bernie" (Sanders) – which suggests he faces an uphill task finding enough new epithets for all the Democrats he faces before 2020.

The president's derogatory descriptors leave flailing opponents either sounding pompously offended, stoically helpless or, in cases when they fire back, like they are coming down to his level (Hello, Joe and your "clown" Trump). An accurate one can be re-used infinitely in headlines and tweets and solidify an opponent's public image.

But will they match those etched into collective memory – Rubio may die as "Little Marco" – or elicit a mere "meh" before being quietly dropped?

HIT: "Low-energy" Jeb Bush

Why it worked: A double-whammy – it made Jeb appear like an entitled scion of the Bush family, running for president out of obligation, not passion, and cast Trump's own hyperactive improvisation in a positive light. This is where it all started: Bush's verbal vanquishing is what announced Trump as a real political player, not just a primaries sideshow, ahead of the last election.

HIT: Pete "Alfred E Neuman" Buttigieg

Why it worked: Trump's obvious angle of attack against the Rhodes Scholar half his age with a formidable military record is his youth, unseriousness and lack of masculinity (but no blatant homophobia!). Calling him Alfred E Neuman after the mischievous MAD Magazine poster boy ticked those boxes, even if Buttigieg did have to look up who it was on the internet, as he claimed. What really made it sing is the physical resemblance, which is not perfect, but definitely THERE.

MISS: "Highly-conflicted Bob Mueller"

Despite the fact that the Mueller Report should not have been authorized in the first place & was written as nastily as possible by 13 (18) Angry Democrats who were true Trump Haters, including highly conflicted Bob Mueller himself, the end result is No Collusion, No Obstruction! — Donald J. Trump (@realDonaldTrump) April 20, 2019

Why it didn't: Credit to Trump for trying to work 'conflict of interest' into a nickname, but the best ones are immediately clear in their meaning, and not a mouthful to pronounce. OK in the context of Trump's own Twitter rants, but no wider traction.

HIT: "Crooked" Hillary Clinton

Why it worked: We can take our politicians as bland and corporate, but add corrupt into the mix and the whole candidacy goes sour. To reposition Clinton from dull technocrat to beneficiary of nepotism with a whiff of personal scandal (Emails! Benghazi! Bernie! Health secrets!) was a major achievement of Trump's first run – and the cinematic nickname did some heavy lifting.

MISS: "Cheatin" Barack Obama

Why it didn't: The previous president's character is not without flaws – he can be vain, cold, and over-confident – and his record is worse. But Cheatin Obama? It just doesn't ring true.

HIT: Elizabeth "Pocahontas" Warren

Why it worked: Once it was just a funny but borderline racist insult – just Trump being his crude self. But then Warren walked right into it and took a DNA test that showed that she had a single Native American ancestor six to 10 generations ago, and doubled down on her false, possibly fraudulent, backstory, to embarrassment from all around. Now the nickname carries her humiliation, and although she is in the top cohort of Democratic candidates, one wonders if she can ever be taken seriously again.

HIT: "Little Rocket Man" Kim Jong-un

Why it worked: It's hard to be scared of World War III when Donald Trump is up there at podium inside the UN quoting Elton John song names at his supposed adversary. By calling Kim Jong-un 'Rocket Man', the president tipped the whole Korean stand-off into the bluffing pantomime it had always threatened to become. After that, it wasn't a surprise when months later the two men were embracing, like two heels at the end of a pro wrestling feud.

MISS: "SleepyCreepy" Joe Biden

Why it didn't: The Democratic nomination frontrunner has a certain hapless amiability that makes him easy to caricature – note the popularity of the Onion-created comic persona in which Biden spent his days in the White House washing his car, thinking up small-time scams and waxing nostalgic about his youth as a free-wheeling ladies' man. But this isn't the side Trump needs: instead of softening him, he needs to play up the threat Biden poses. "1 Percent Joe" didn't do Trump himself any favors and rang hollow, "Sleepy Joe" was too mild, "Creepy Joe" again shines a light on the president's own indiscretions, while "SleepyCreepy Joe" – the current incarnation – looks like Trump can't make up his mind, so lacks conviction. There is still time.

By Igor Ogorodnev

Igor Ogorodnev is a Russian-British journalist, who has worked at RT since 2007 as a correspondent, editor and writer.