FDR's tenure might have created an amendment to that effect, but it's not like this administration hasn't used a legal loophole before.

Perhaps there's a war, that a misguided congress won't declare as such, and a certain vice president that runs for president, with a certain someone as his vice president...

See https://www.culawreview.org/current-events-2/the-22nd-amendm...

Specifically section on martial law in wartime context. It’s not very clear but I just feel like the norms and laws will be stretched or broken, as the administration has already done numerous times.

Not constitutionally, at any rate.

… not yet. The problem with a norm breaking presidency like Trump’s and the GOP power structure is that no norm is safe, including elections.

Zelensky's presidency was supposed to end couple of years ago. Would it be different in USA?