Doyle, at the time we're talking about, Arkansas was part of the Trans-Mississippi District of Department No. 2, with Johnston as department commander and Beauregard as his immediate subordinate; so moving Van Dorn around was simply an intra-departmental movement. The irony is that Van Dorn missed both fights (New Madrid and Shiloh) and when the Trans-Mississippi Department was established as a separate command after Shiloh, Van Dorn's men had the door shut behind them and remained east of the Mississippi (until they were captured at Vicksburg and Port Hudson and exchanged back in Arkansas).