How could we invent a realistic situation in which a nation-state (or even just a centralized enough East Asian kingdom) dominated ethnically and politically by the Hmong-Miao people manages to emerge? IIRC, the Hmong population, unlike a number of other ethnicities in Southeast Asia and Southern China, never truly coalesced around a single territory that they could more or less call "theirs", in the vein of post-Westphalian ideology. So far, by looking at a few maps, the only region in which they really constitute a majority is the northern part of the Laos-Vietnam border. So, where, when, and how could a Hmong state be created?
Perhaps if the French authorities in Indochina opt for creating an autonomous entity for them before they leave? Or if pro-US forces manage to defeat the Pathet Lao in the Laotian Civil War, diminishing the possibility of there being an equivalent to the ethnic cleansing suffered IOTL by the Hmong at the latter's hands, paving the way for an autonomous republic under Laotian tutelage?
Perhaps if the French authorities in Indochina opt for creating an autonomous entity for them before they leave? Or if pro-US forces manage to defeat the Pathet Lao in the Laotian Civil War, diminishing the possibility of there being an equivalent to the ethnic cleansing suffered IOTL by the Hmong at the latter's hands, paving the way for an autonomous republic under Laotian tutelage?