The amendment says anyone who “engaged in insurrection or rebellion” against the Constitution after taking an oath to defend it is ineligible to hold office, and a long-shot effort to employ it is growing.
In the last state that tried this, it failed. From my understanding, he must first be found guilty of having committed a crime which disqualifies him. No matter how obviously guilty he is, this seems like a necessary first step, although IANAL.
The amendment was instituted in the wake of the Civil War, and was used several times against members of the Confederacy who never had a trial or conviction.