How the 25th Amendment works:

1. Pence and a Cabinet majority send a letter to the President pro tempore of the Senate (Grassley) and the Speaker of the House (Pelosi) stating Trump is unable to discharge the powers and duties of his office. Pence becomes Acting POTUS.

2. BUT Trump become POTUS again if he sends Grassley and Pelosi a letter stating no such inability exists.

3. UNLESS Pence and a Cabinet majority send Grassley and Pelosi a second letter stating Trump isn't able to do his job.

4. THEN it's up to Congress. Pence remains Acting POTUS if 2/3 of Congress determines Trump isn't able to function as President. Otherwise Trump becomes POTUS again.

5. WRINKLE ONE: Three of the 15 Cabinet Secretaries (Defense, AG, DHS) are Acting. Their legal status and role under the 25th Am is unclear. Though that might not matter if majorities of both the whole Cabinet and Senate-confirmed Secretaries declare Trump unable to do his job.

6. WRINKLE TWO: There are only 99 Senators right now since Georgia Senator David Perdue's term expired Sunday and Jon Ossoff hasn't been sworn in yet. That means 66 Senators are needed to vote to remove Trump, not 67. That could be crucial in a close vote. /end