It’s called a plea bargain.
He pled guilty to a crime to avoid trial.
Only shows that the present US justice system is a joke.
Any other country that I know off - the charge involving a murder is defined/set by the prosecutor - in that case: premeditated murder
It is then up to the judge to pass sentence based on the prosecutors initial charge; premeditated murder or change it to e.g. manslaughter, depending on e.g. witnesses or evidence that might change a premeditated murder into a manslaughter charge.
Therefore in this case - either death-sentence, a life prison-term or e.g. 30 years prison-term.
The accused - who could then plead guilty to the respective charge, before a sentence is passed (exchange of a confession for a sentence concession) - might receive leniency aka a reduction of the sentence.
As such a death or life sentence being reduced to e.g. 30 years - or a 30 years term reduced to e.g. 20 years.
In the USA, a court and it's system is obviously a mere
trading bazaar (see the word plea-
bargain in order
to avoid a trial) and NOT a place of justice.
That the rich and powerful (the elites) aka US politicians - do not want to change that judicial procedure is understood.
So if e.g. Trump strikes his bargains and gets off scot-free, then don't complain later about Trump or MAGA or Republicans or whoever.
It would only make you look plain stupid.