They are good examples of policies that don't have a victory strategy (as opposed to exit strategy). Bush Jr., Powell, and Rumsfeld all had different visions of what was to be accomplished and what was not.
Powell sold the idea that "if you break it, you have to fix it". Rumsfeld believed we didn't have to fix anything. And Bush Jr. fumbled with efforts to democratize Iraq, thinking that a military victory was "mission accomplished", being unprepared for a war of insurgency.
Then, and now, I don't believe if you break it, you have to fix it. The US has had plenty of trauma in wars of occupation, and it simply isn't economically or politically acceptable to become mired in such wars. Three months after it was clear there was no WMD, Saddam had been captured, and the mission was done. Leaving Iraq to its social and religious madness was probably the best and far less expensive strategy.
As far as Afghanistan is concerned, it was a low intensity operation and the calculus was simple: the cost of staying vs the cost and consequences of leaving. Is it better to leave and presume one might have to invade once every decade to crush terrorists or is it better to pay the price indefinity?