Was there ever a clear exception stating that you're ineligible for a Nobel in regards to stopping a war that you yourself started?

The Peace Prize has had quite a few weird choices, like Kissinger when that simply meant the USA would stop participating in the Vietnamese civil war (and to be generous putting a stop to USA bombing campaigns that Kissinger advocated in Vietnam and surrounding countries) or Barack Obama for giving a few speeches after less than a year in office. So it's not out of the question but it's hard to see the logic behind Trump getting one now.