You quoted George as saying:
"It has long been said that presidential candidates make promises but do what they want if elected. In foreign policy, presidential candidates make promises and, if elected, do what they must to get re-elected...

...Any president who simply withdrew forces from Iraq without a political settlement would find himself or herself in an enormously difficult position. Indeed, such a president would find himself or herself in a politically untenable position."
Just so. The Politicians are NOT talking policy, they're talking politics and the bulk of it can be safely ignored. As you say, they "don't have even a decent layman's understanding of the history and complexities of these conflicts."

Yep. Nothing much new in that...