Johnson right now has a popularity rating of about 24% among Britons, across different polling. (For comparison, Biden’s approval rating among US adults is about 41%.)
Both Truman and Bush saw their parties suffer once-in-a-generation defeats in the following election. Their parties lost the presidency in blowouts and endured losses in the House and the Senate.
Brown’s Labour Party lost the next general election, and he was replaced as prime minister. This has been a theme throughout the last 45 years in UK politics.
Every single prime minister whose popularity dipped to Johnson’s level failed to recover. They either resigned the prime ministership (like Tony Blair) or lost the next general election (like Brown or John Major).
Biden isn’t anywhere close to being in the same straits as Johnson. While Biden isn’t as popular as he once was within his own party, he is unlikely to face any serious challenge if he decided to run for another term for president.
Moreover, Biden knows that there is plenty of history of presidents as unpopular as he is improving their position and actually winning another term in office. Ronald Reagan (in 1983) and Truman (in 1946) were less popular later in their terms than Biden currently is and won the next presidential election.
More recently, Barack Obama, after the 2010 midterms, was nearly as unpopular and won a second term. Trump almost won a second term, even as he was more unpopular at multiple points as Biden.
Even if the 2024 election were held today, it’s not clear Biden would lose. He’s basically running even with Trump, who remains his most likely opponent. Biden is benefitting from the fact that presidential elections are ultimately choices, and the non-Biden choice is as unpopular as he is.
Johnson, on the other hand, isn’t likely to benefit from facing such an unpopular adversary. Labour Party leader Keir Starmer isn’t beloved, but his net popularity ratings are as good if not better than Biden’s (depending on the poll).
Of course, most voters won’t get to vote directly for Johnson or Starmer in a general election. They’ll be voting for candidates representing the Conservative, Labour and other parties in their own constituencies (or districts).
On this metric, Johnson is in worse shape than Biden. Johnson’s Conservative Party is trailing in every single reputable poll to Starmer’s Labour Party. The average deficit is running in the high single digits. It’s one of the worst positions the Conservative Party has been in the last decade.
But perhaps the best way to look at Johnson’s vs. Biden’s situation is to understand that both may not win the next general election, though it will likely happen in very different ways.
Biden may voluntarily decide not to run because he’ll be in his 80s by the next presidential election.
Johnson may be forced out because of how deeply unpopular he is.