Sentence:  Indeed, it may turn out to be a <WSD>Trojan horse</WSD> that finally allows conservative ideologues, who have unsuccessfully laid siege to Medicare since the days of Barry Goldwater, to breach its political defenses. 
Meaning of the word marked with <WSD> tags:  A person, organization, social movement, piece of legislation, or ideology with a negative agenda or evil intentions under the guise of positive values or good intentions.