Hypothetical: Former President/Current Speaker of the House wins next election, could current President sabotage?

Kind of inspired by but not directly related to the current House Speaker race. Assume we are in a completely alternate universe where the Schmapublican winner of the 2016 election loses the 2020 election and a 2022 House Speaker selection goes so awry that this person becomes the compromise House Speaker. They mount and successfully win their 2024 presidential campaign but the House and Senate both go to the Fredocrats. Also, assume in this alternate universe that people actually care about the constitution and casually breaking with the constitution because it’s inconvenient for you is unthinkable.

In this scenario, could both the President and Vice President resign on the day before the inauguration? The Speaker of the House would automatically become President, thus, would have served two “terms” and become ineligible for third term. Also assume in this scenario that the VP-Elect is someone like Arnold Schwarzenegger who is also ineligible for president, thus, the role would go automatically to the Fredocrat House Speaker-Elect and the Fredocrats would hold the presidency despite losing the election?

Is that how things would go in this, admittedly highly contrived scenario? Can the House Speaker decline their role in the line of succession? Would the House Speaker preventatively resign as Speaker the moment the election was called just to avoid this? Are there any other ways this scenario could play out?

If the person taking over the presidency does so more than halfway into a term it doesn’t count towards terms served, which is why LBJ was eligible to run for reelection in 1968 although he chose not to. And I don’t think the presidency is transmitted automatically like it’s a monarchy; the act of taking the oath of office is what makes you president, not some divine act of succession.

The requirements to be elected VP are the same as those for president, so Schwarzenegger wouldn’t be eligible to be VP-elect in the first place.

Also, there would presumably no longer be a “Speaker-Elect” at this point, since Congress convenes several weeks before the inauguration; your “Fredocrat” would be Speaker and the former president would be the former Speaker.

I’m fairly sure you can’t force someone to be president against their will - if they don’t want to take the oath of office, then presumably Patty Murray, who as president pro tempore of the Senate is next in line (and as of writing is second in line since the Speakership is sede vacante) would get the job for a day and get to be an interesting historical footnote like President Atchison.

As @Smapti says, a term must be more than two years to count. Another consideration is that while the Vice-President becomes President if there is a vacancy, any other person that succeeds becomes acting President. Surely the Constitution makes a distinction but what exactly that is I don’t think anyone knows; but it may mean that even if the SotH becomes acting President for 2 years + 1 day, it still may not count against them as far as term limits.

Except Atchison was never President - acting or otherwise. Taylor still became President at noon; he simply couldn’t discharge his duty until he took the oath. In the scenario you gave Murray would be President for a day.

Or think of it this way, if Taylor didn’t become President without taking the oath of office, then how did Atchison become President without taking the oath either.

Incorrect. You become Present upon the vacancy, you just can’t discharge your duties as President until after the oath.

Only if you’re the vice president.

Let’s see what the 25th Amendment has to say

In case of the removal of the President from office or of his death or resignation, the Vice President shall become President.

Look for yourself, nothing about taking the oath, But let’s look at the President-elect’s situation
Article II Section 1

Before he enter on the Execution of his Office, he shall take the following Oath or Affirmation:– I do solemnly swear (or affirm) that I will faithfully execute the Office of President of the United States, and will to the best of my Ability, preserve, protect and defend the Constitution of the United States.

Not “Before he becomes President”, but “executes his office.” “Isn’t that the same thing?” you ask. Here is what Cornell Law School has to say about it.

What is the time relationship between a President’s assumption of office and his taking the oath? Apparently, the former comes first, this answer appearing to be the assumption of the language of the clause. The Second Congress assumed that President Washington took office on March 4, 1789, he did not take the oath until the following April 30.

What about the Presidential Succession Act of 1947? Here there is a delay as the Speaker of the House or President Pro Tempore of the Senate must resign their office before becoming Acting President. The same is not true for the Cabinet members. If Murray were to die and assuming no Speaker (still) then if Biden and Harris both die then Antony Blinken would immediately become Acting President.