Most educated guesses assume that Trump and Johnson are “secretly” talking about installing Trump as president through a “contingent election,” whereby the House of Representatives, not the Electoral College, determines the president. I think the plot goes deeper than that, but let’s start with the contingent election idea.
To understand how this could work, you have to understand the 12th Amendment of the Constitution. Here’s the key language: “The person having the greatest number of votes for President, shall be the President, if such number be a majority of the whole number of Electors appointed; and if no person have such majority, then from the persons having the highest numbers not exceeding three on the list of those voted for as President, the House of Representatives shall choose immediately, by ballot, the President. But in choosing the President, the votes shall be taken by states, the representation from each state having one vote[.]”
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Let’s say Vice President Kamala Harris wins the bare majority of Electoral College votes necessary, 270, but the Republican legislature in Wisconsin refuses to submit the state’s 10 electors by the deadline. In this scenario, the new total number of electors becomes 528, not 538—and Trump needs only 264 electoral votes to “win.” If you take Wisconsin and Nevada’s six electors out of the mix, Trump needs only 262 electoral votes to “win.” He’ll likely achieve those numbers without having to win one of the “blue wall” states.
It’s possible to play with the numbers until you find a “tie” scenario at which point the contingent election goes to the House of Representatives, but the far more likely situation is that Trump decreases the overall number of electoral votes available until he can claim a majority of the ones remaining.
And this is where Speaker Johnson becomes critical to the whole “secret” plan. In 2020, Nancy Pelosi was speaker of the House. If states had tried to get cute and not submit their electors by the December 11 deadline, Pelosi would just have extended the deadline. But Speaker Johnson surely won’t. If electors are not submitted by December 11, he’ll likely declare the process “over” and say that the electors appointed by that date are the only ones allowed to vote for president.