The decline seems to be driven by his leadership of the chaotic, bloody withdrawal of American personnel from Afghanistan. But the continuing pandemic and disappointing economic news, including a weak jobs report on Friday, probably won't help.
Democrats should definitely worry about the implications of Biden's slump for congressional elections in 2022 — and beyond. It's worth remembering, though, how consistent the pattern of declining approval and midterm losses has been among recent administrations.
By this stage in his presidency, Donald Trump's approval was under 40 percent, setting up big Democratic victories in 2018. By 2010, Barack Obama was polling in the low forties, setting up the biggest Republican gains in the House of Representatives since the 1930s. George W. Bush and his party initially escaped that fate, benefiting from a surge of support following 9/11. By the middle of his second term, though, he was polling well under 50 percent, leading to Democrats winning majorities in both houses of Congress for the first time since 1994 — when Republicans benefited from an early collapse in support for Bill Clinton.
It's not just Biden's approval trend that resembles previous presidents', moreover. No 21st century president has left office with a Gallup average over 50 percent.
These observations suggest Biden's woes are not solely attributable to the specific shortcomings of his leadership or policies, real as they are. In a highly polarized environment, it's extremely difficult for any president to sustain majority support. That's partly because recent presidents had little margin for error: Bill Clinton, George W. Bush, and Donald Trump all took office with pluralities or minorities of the popular vote. But even Obama, the only two-time popular vote winner since Reagan, struggled to translate big promises of hope and change into a successful agenda.
There's a precedent for the present situation in the 1970s, when a series of weak executives struggled to deal with challenging domestic and international circumstances. Looking farther back, we might find parallels in the period between 1876 and 1896, when just two presidential candidates won more than 50 percent of the popular vote. Either way, unpopular presidents have become the norm rather than the exception. We should adjust our expectations accordingly.