If the question is asking about Trump, Orban, Putin, or your other favourite dimwitted world leader, it’s because these people usually don’t actually want to fuck everything up. They want to make their country (or their notion of the groups of people they regard as their country) prosperous and glorious. But they’re just unable to take in the fact that their policies and leadership are actually leading them further away from this goal. It really is just a deadly combination of incompetence and inability to self-criticise.

In the case of Trump, who is a pre-eminent example of this, he really does think that tariffs will make the US richer. He is a moron, of course, but that’s what he thinks. He doesn’t “know” that tariffs will damage the American economy and America’s international reputation, because he doesn’t grasp the concept at all. Anyone who has observed his thinking for any period of time after he got into politics can observe that it is very feelings-driven and not very fact-based. And a lot of his government’s policy is also ego-driven, which explains why it is seemingly always falling for Russian propaganda and why he wants to be on good terms with Putin. Though Putin is no universal genius either, one thing that he is very good at, as a result of his KGB training, is manipulating others to get what he wants. It certainly does help Putin a lot that Trump is pretty easily manipulated. And as for Trump’s comments about wanting to take over Canada, take over Greenland, take over Panama, &c. &c., most non-US observers describe that as clear evidence of his mental decline. J. J. McCullough, a Canadian political commentator, described it as being “obvious” that Trump is “losing it”.

And ironically, since Joe Biden’s mental competence was called into question in the last US election, while Biden’s senility manifests mostly in the form of stutters, speech blunders, and random mostly-inert goofiness, Trump’s senility seems to manifest in a desire to take over the world and become God-emperor of Mankind, which is objectively more dangerous for a world leader.

Inb4 Donald Trump calls for all of them to be sent to Gulagtanimo Bay.

There’s also the possibility of appeals to get the sentence reduced. And the defendant’s family can apply for pardons. Pardons and commutations are usually associated with political grift in the US (and this is a well-deserved reputation), but they can also be applied for and governors occasionally grant them to prisoners who demonstrate they’re reformed even when they’re not otherwise eligible for parole.

Grovelling before the judge and acting like you accept you are guilty for sixty minutes costs nothing on the part of the defendant anyway.

Even though by the time the hearing commences, the judge has already usually decided on the sentence, every competent criminal defence lawyer will advise their client to grovel and beg for mercy at the sentencing for two reasons:

1. Acting recalcitrant could upset the judge and result in a heavier sentence than the judge originally planned because they feel a need to make an example of the defendant.
2. Not being apologetic damages your future chances of parole when the parole board looks at the tape or record of the sentencing.

I’m surprised that Sanders is older than both Trump and Biden but retains about twice as much virility as either of them and about four times as much sanity as Trump

Agreed. I managed to get my grandpa onto Linux using Mint on his old computer. He said the interface resembled classic Windows and was up and running in less than five minutes. I just had to show him how to use the software manager and that’s it.