PROVO, Aug. 12 -- Tyler Robinson sat in a Utah County jail cell on Tuesday as his attorneys submitted the argument that may determine whether he stands trial for his life, a written brief closing the pre-hearing phase of the case against the 23-year-old accused of assassinating Charlie Kirk at Utah Valley University nearly a year ago.

Defense attorneys filed their written argument with Judge Tony Graf of the 4th District Court in Provo on August 11, responding to prosecutors who called their case "as straightforward a bind-over decision as this Court will ever see." The filing sets the stage for closing arguments on September 1, after which Graf will decide whether Robinson faces a capital murder trial.

The momentum of the case has buil...