The following Presidents never got that low: Obama, Clinton, Ford, Kennedy, Ike.
Reagan and Johnson hit lows of 35% and Bush the Elder dropped as low as 29%.
Once you get lower than that, you're in the zone of total long-term fuck-uppery:
- Bush the Younger (25%) needed to start a costly, unnecessary war under false pretenses.
- Harry Truman (22%) and Jimmy Carter (28%) required weak economic conditions and years of screwing up situation after situation.
- Richard Nixon (24%) ...well, we all know what kind of shenanigans he was up to.
Gallup concludes: "Presidential job approval ratings are fluid, and all presidents have seen both upward and downward swings in their ratings at various points in their administrations -- a historical precedent indicating Trump's approval could drop further or recover in the weeks and months ahead. An encouraging sign for Trump, perhaps, is that all presidents whose ratings fell below 36% -- with the exception of Nixon -- saw their ratings improve thereafter. Clinton provides a particularly relevant example. His approval rating dropped to 37% in June 1993 but recovered to 56% by September of that year."