The US started the entire Iraq war with so called "Intelligence" telling them that Saddam had WMDs, and without any concrete evidence attacked anyway and when it was over no WMD was ever found...
Now compare that to North Korea where there is an insane dictator firing and playing with CONFIRMED nuclear weapons WITNESSED by the entire world and aiming their missiles at Japan, South Korea and the US... The US would be seen as a hero if it finally ended the abusive North Korean dictatorship.. it's only a matter of time