In a classic October surprise, Donald Trump is forcibly sequestered in the Oval office by a contingent dispatched by the Pentagon. The President's family is fathered up and held prisoner at the Trump Towers. The President's family is essentially held hostage but they are alive so long as what the President's captors say. The cover story is that the President has taken ill as has many in Cabinet. The President "voluntarily submits to the 25th Amendment and resigns for "health reasons". Meanwhile, a fake virus is sweeping America and the UN has already emerged under the Kigali Principles to take over the handling of this co-called epidemic which involves the unveiling of FEMA camps which are ostensibly being used as quarantine centers (ie detention centers).
Nancy Pelosi is sworn in as President and Hillary Clinton is appointed to be the Vice-President. It is the presumptive assumption that Hillary will become the President in 2020 as all campaigning at the Federal level is suspended in order to prevent Russian tampering with our elections.
Effectively, Trump is deposed and the country goes under medical martial law under the assistance an auspices of the United Nations.