Though the “true intentions” and effectiveness of his plan are debatable, what is being done is for the sake of Iraq, which in turn affects the security of our nation.
If debatable, I would disagree that the motivation for what is being done in Iraq has anything at all to do with benefitting the Iraqi people. Benefits might well be side effects but they never informed the motivation - except in so far as they assisted and enabled expression of the motivation.
The core motivation? Security of your nations (and by extension mine) desire for a secure oil supply. Secure oil supplies mean world economic stability.
Someone has to have a grip on the balance of power in the region. It might as well be the U.S.