I think the basic point of comparison, that Bush decided to open up a second and even more difficult front when he had not secured the initial war zone, is right on.

The argument that a nation cannot win a two-front war is quickly disproved by example of the United States in WW2 which defeated both Japan And Nazi Germany, literally on opposite sides of the globe.

Bush is not losing the war in Iraq because he didn't secure the "initial war zone", i.e., Afghanistan. He is losing there today for different reasons.

If, e.g., the attacks on 9-11 hadn't occurred, and the US didn't attack Afghanistan, but did go ahead and invade Iraq, I believe Bush would still be losing the fight there, due to (1) Incompetent leadership, (2) Lack of national and international support due primarily to the immoral reasons and lies used to start the war, and, (3) A determined local insurgency willing to fight to the death.