So it was time for step four: Blame Donald Trump. Starting in mid-May, Mr. Biden denounced Mr. Trump for leaving office with the country “on the brink of a Great Depression.” This was so implausible that Mr. Biden reverted to attacking oil companies, demanding that industry CEOs “take immediate actions” to supply more gasoline and diesel fuel and that gas station owners “bring down the price you are charging” (they make a few pennies a gallon). “Do it now,” the president ordered.

Neither approach worked. A Harvard CAPS Harris Poll released on June 29 put Mr. Biden’s disapproval rating on the economy at 68%.

Next up was step five: Appear to be doing something—anything. The president proposed a three-month gas-tax holiday, said he was considering student-debt relief, and signed a bill to investigate ocean shipping rates.

Which brings us to step six: Abandon ship. As Mr. Biden flounders, candidates in tough races will realize that they risk being sucked down as he sinks and begin to distance themselves from the president. They’ll express mild disagreements at first, but as November gets closer, expect more Democrats to break with Mr. Biden, some with harsh criticism of his policies and leadership.