an accused person is also presumed innocent.
All that that phrase means is that guilt has to be established in court, not innocence. It means that not guilty is the default position if neither guilt nor innocence can be established in court, that the prosecutor has the burden of proof. Defendants are not viewed or treated as innocent. If they were, they wouldn't need lawyers.
The charges Trump faces are serious, precisely because they are politically based.
The charges are based in the indictments handed down by grand juries after hearing and seeing evidence of crimes, which is what prevents purely politically motivated prosecutions from going forward.
his political adversaries are trying to use the courts because they can't fight him in the ballot box
Trump can't win an honest election. He was beaten decisively by Biden in the last election, when Trump had the incumbent advantage and Biden didn't. If they both run again in 2024, that will be reversed, plus Trump is dealing with the stigma of being a defendant and appearing increasingly confused, not to mention a booming economy with record low unemployment, inflation coming under control, gas prices down, and record high stock prices.
And once again, his political rivals can't use the courts unless they can present sufficient evidence of crime to a grand jury to get an indictment. Trump is a thug, which is why grand juries everywhere are indicting him. He's done. Unless he drops dead prematurely, his fate is a given. He will die broke in prison, disgraced, his legacy in tatters, his mind reduced to mush - just like Giuliani.
It is also another reason that when Democrats in a survey say they want him executed it is quite serious and troubling.
You're troubled that people who love their country and its Constitution want the man who defiled it executed by government he attacked? I'm not. That's justice. Like the knuckle-dragging, mouth-breathing thugs who attacked the Capitol for him, Trump fooled around and is now finding out.