@SM Well a big problem is after invading Iraq they did not find any evidence of a such a nuclear program. After Desert Storm Saddam was forced to destroy his stockpiles and programs and indeed all evidence points to the fact that indeed he did. Even before they went in they were told there was no evidence of such a program by IAEA. Furthermore the UN actually did not approve of the US invasion of Iraq.
CNN.com - Nuclear chief: No 'smoking gun' in Iraq - Jan. 7, 2003
Operation Desert Storm is good though to investigate and I agree indeed with a lot of what you say about the Desert Storm facet. The difference between Desert Storm and the Iraq War (2003-present) is quite vast. Desert Storm was justifiable, Saddam had invaded the sovereign nation of Kuwait. There was a clear cut end goal to Desert Storm. America was asked to intervene. America pushed Saddam out of Kuwait and broke his army to pieces. When this was accomplished the US forced Saddam to surrender and dismantle his weapons programs. When you actually can justify a war and have an end goal you can actually win it. Compare this to the Iraq War in which there is no justification for it, there was never any sort of end goal, and indeed the war is still going on over there.
As far as political capital goes, because we invaded Iraq our European allies do not want to go to war with Iran or north Korea despite the fact they do actually have a nuclear program. A big part of why the US errs in participating in this Iran Deal is because of the Europeans. The Europeans because they do not want to go to war with Iran and suffer a catastrophic failure as they did in Iraq, have fallen into their appeasement mentality and think they can actually deal with these insane regimes.
Containment policy is not appeasement. Appeasement is giving them what they want, giving them aid, giving the money, giving them land. Containment policy is such things as sanctions, isolating them, and refusing to deal with them.
As for loss of trust by the American people. You yourself noted elsewhere that people support Trump and Sanders. The one commonality between Trump and Sanders is both at the time of the Iraq invasions counseled against invading Iraq. Indeed one of the top reasons people don't trust Hillary is because she also voted to go to get involved in Iraq. Furthermore, a lot of people believe in the 9/11 inside job conspiracy theories because of the Iraq invasion. It displays a deep seated distrust of the US by its own people. In fact most the people I have met in person that believe in the 9/11 conspiracy theories are actually veterans of the Afghan and Iraq Wars. Their participation in those wars is directly linked to their belief 9/11 was an inside job.
As for the endless insurgency. The war in Iraq is still on-going and has no immediate end in sight. The followers of islam were there all ready. Iranian backed forces were in Iraq all ready, and when their biggest enemy Saddam was toppled they moved in to fill the vacuum. Ironically America is currently supporting the Iranian backed elements in Iraq to fight the followers of Islam.
There are always options indeed. Why then limit ourselves to war options? In the case of north Korea, things are further complicated by China. If we go to war with north Korea we run the risk of going to war with China. Going to war with China is no light matter. This has happened before even in the Korean War and is what set the stage for the current situation pertaining to north Korea.
As for the end of time that will have to happen eventually, but before then the beginning of sorrows. Wars and rumors of wars and nation rising up against nation, but the end is not yet. Remember, blessed are the peacemakers.