War will be defined by Wikipedia entry on this page: 

https://en.m.wikipedia.org/wiki/List_of_wars_involving_the_United_States

 (“intervention” doesn’t count, has to have “war” in the title). US troops must be involved. Iraq war would’ve counted as yes, Ukraine war would’ve been no. For woman President it would resolve yes as soon as she is sworn into office.

Clarification: the Gaza war does not count as the US involvement is extremely limited

Example: The "Twelve-day war" does not count because US troop involvement was not sufficient (no boots on the ground).

Examples of wars that would have triggered this market: Iraq War, Afghanistan War.