Machine can be used for Vote. Vote is related to Politics. Party can be used for Politics. Contractor is a type of Party. 
Discourage is the opposite of Recommend. Recommend is a synonym of Advocate. Advocate is a synonym of Preach. 
Machine --UsedFor--> Vote <--RelatedTo--> Politics <--UsedFor-- Party <--IsA-- Contractor 
Discourage <--Antonym--> Recommend <--Synonym--> Advocate <--Synonym--> Preach 