I don’t think this is real. You can’t force a sitting president into court unless he is impeached.
The aren't trying to force him into court. They are letting him know that he won't be on the ballot if he does not show up in court. It's up to him to go or not.
It's his call. Show up and testify, or ignore and stay off the ballot. *HE* wants something from the state, not the other way around.
The Supreme Court in Clinton v. Jones decided that POTUS is not immune from civil courts. (Thanks Bubba!). Barry cannot ignore a civil court.