both Trump and Biden become nonviable either legally or via ill health or death
the Dems and Repubs scramble to find candidates, but they are all terrible 
the PSL ticket takes the White House and uses all the extralegal powers granted to the Executive Branch over the decades to upend capital power across the US
Biden could be in hospice and Democrats would still run him. Trump could be in prison and Republicans would still run him. And this is the country that calls other countries corrupt.