Filtering/Searching fields with enumerated data (e.g. Smart Map) in an ElementCriteria model

I have an ElementCriteriaModel in which I need to find elements that contain a particular value for “state”, which is a property of a “Smart Map” field ($element->smartMapField->state).

Filtering after a find would be easy, but I need to do this in the ElementCriteriaModel, as I am passing it to the ‘criteria’ option for ElementAPI (https://github.com/pixelandtonic/ElementAPI).