I think if we could get the low hanging fruit, the smaller countries without much in the game, to declare it genocide, that would put pressure on the larger countries.

Some interesting info:

To pass a resolution in the United Nations General Assembly, a simple majority of the members present and voting is required. With 193 member states, this would generally mean at least 97 votes in favor, assuming all members are present and voting.

Just 97 countries is all it would take to get that ball rolling. Screw the US, put pressure on Guatemala! Work from the bottom up.