Complex sentence: Whiteley became Chief of Intelligence (G-2) at SHAEF instead of Strong, but Eisenhower and Smith eventually had their way and Strong assumed the post on 25 May 1944, with Brigadier General Thomas J. Betts as his deputy.
Split into simpler sentences: Whiteley became Chief of Intelligence (G-2) at SHAEF. However Eisenhower and Smith eventually had their way and Strong assumed the post on 25 May 1944, with Brigadier General Thomas J. Betts as his deputy.