Absent some kind of sanctions against NK, the NK government would likely commit their own acts of war against other countries that would involve bloodshed. There are also other military conflicts that produced better outcomes than the probable outcome had the US military not gotten involved.
Produced and supported completely by your imagination. Sanctions are not preventing North Korea from starting a war. They have advanced their military technology with maximum sanctions. They developed a hydrogen bomb and ICBM during maximum sanctions. The sanctions are intentionally immoral because the US knows they do nothing but cause suffering on the Korean people with the hopes that it will turn them against their leadership. This is what the US does all around the world; obtain power and influence by usurping leadership with the intention of destabilizing the country. The US end goal is civil conflict.
I'd love to hear what military conflict you think US involvement made better. Japan and Germany are the only ones for which I could even imagine someone putting up an honest argument on behalf of US involvement.